3Com 56K инструкция обслуживания

® http://www.3com.c om/ 3Com Of ficeConnect 56K Business Modem Command Refer ence Publishe d Janua ry 1999[...]

3Com Corporation 3800 Golf Rd . Rolling Me adows, Illi nois 60008 Copyright © 1999, 3Com C orporatio n. All right s reserved. N o part of this doc umentatio n may be reproduced in any form or by any mean s or us ed to make a ny derivative work (such as tran slation, tr ansformati on, or adaptati on) with out writt en perm ission from 3Com C orpora[...]

C ONTENTS A BOUT T HIS G UID E Introduction ............ ............. ................... ............. ................... ............ 1 Finding S pecific Inform ation in Thi s Guide ............. ............. .................. 2 Convention s .................. ............. ................... .................... ............. ..... 2 Relate[...]

Setting up your ISP information ...................... ............. .............. 1 -16 Other Operating System s ............ ...... ....... ...... ...... ....... ...... ....... ....... 1 -17 If Y ou A re Using W indows 3 .x ........................ ............. .............. 1 -17 If Y ou A re Using MS-DOS .................... ............ ...[...]

Call Detection ......... ................... ............. ................... ............. ......... 4-6 Caller ID Functions ........ ....... ...... ....... ............ ....... ...... ....... ...... ....... .. 4-7 Service T ypes ......................... ............. ................... ............. ......... 4-7 Applica tions of Caller ID T e[...]

Controlling Link S peeds with &N and &U ............. .................... ......... 8-4 Controlling Link Speeds ......... ...... ....... ............ ....... ...... ....... ...... ... 8-4 Limiting the Highes t Possibl e Conne ct Speed .. ............. ................ 8-4 Limiting the Low est Possib le Conne ct Speed ... ..................[...]

Software Flow Con trol .... ................... ................... ............. ....... 1 1-2 Received D ata Flow Con trol ........ ............. ................... ............. ....... 1 1-3 T ransmi t-Data Flow Control ........ ............. ................... .................... 11-5 12 H ANDSH AKIN G , E RR OR C ONTR OL , D ATA C OMPRESSI[...]

Digital Loop back T esting (A T&T3) ........ ................... ............. ....... 1 4-5 Remote Digi tal Loopback T esting (A T&T6, A T&T7) ............... ....... 14-6 Granting a D igital Loopb ack T e st Request (A T&T4) . ............. ....... 14-6 Canceling All Dig ital Loopba ck T e st Reques ts (&T 5) ............. ...[...]

Getting Ne w Operatin g Software ................. ............. .................... 16-2 Sendin g New Software to your modem ... ................... .................... 16-2 If Y our Mod em Doesn’t Res pond ............. ................... .................... 16-4 A S-R EGISTERS Understand ing Bit-Mapp ed S-Regi sters .......... ............[...]

Additiona l Sp ecific ations . ....... ...... ............. ...... ....... ...... ....... ...... ... E-3 Serial Ports ... ...... ....... ...... ....... ...... ....... ............ ....... ...... ....... ...... ... E- 3 The EIA-23 2 Interface ............ ...... ....... ...... ...... ....... ...... ....... ......... E-4 Wi ring a DB -25 to DB-9 Cabl[...]

A BOUT T HIS G UIDE Introduc tion This guid e is a command r efer ence for t he 3Com Of ficeConnect 56 K Business Mod em. It includ es informat ion about A T commands, S-Regi sters and tro ubleshoot ing. If t he info rmatio n in the re lease notes shi pped wi th y our prod uct di ffer s from th e inform ation in this g uide, fo llow the instru ctio[...]

2 A BOUT T HIS G UIDE Conv entions T able 1 an d T able 2 list conv e n tio ns th at a re used throug ho u t this gu id e . T able 1 Notice Icons Icon Notice Type Description Informatio n note Important features or instructi ons Caution Inform ation to aler t you to potentia l damage to a program, sy stem, or device Warning Inf ormation to a lert y[...]

Related Do cumentation 3 Relat ed Docum entation The 3C om Off iceC onn ect 56 K Bu siness Mod em I nstal la tion Gui de should be used for the insta ll a tio n of the Bu s in e ss Mo de m . Y ear 2000 Compliance For in formati on on Y ear 2 000 c ompl iance and 3Com products, v isit the 3Com Y ea r 200 0 we b pag e: http:/ /www .3com.com/pr oducts[...]

4 A BOUT T HIS G UIDE[...]

1 C ONNECTING TO Y OUR ISP This c hapter c ontains infor mation about c onfig uring your m odem fo r various opera ting systems. ■ W indows 95/ 98 ■ W indows NT 4.0 a nd Late r ■ Macin tosh ■ Other Operating Systems Windo ws 95/ 98 The first time you start W indows 95/9 8 after you’ve inst alled the m odem, Windows 95/98 will aut o -detec[...]

1-2 C HAPTER 1: C ONNECTING TO Y OUR ISP 3 When the fo llowing wi ndow appear s, i nsert your C onnections CD - ROM, change the de fault driv e in Cop y Manu facturer’ s files from: to D: (or the correct path of your C D-ROM) a nd click OK to insta ll the I NF file. 4 Windows 95/98 displa ys a window asking yo u to choose your modem type fr om t[...]

Windows 95/98 1-3 Step O ne: Determ ine if D ial-Up Ne tworking is In stalled 1 Click Start | Settings | Co ntrol Pan el . 2 On the Con trol Panel, do uble-click on Network . The Network widow will appear . 3 Return to the C ontr ol Panel an d doubl e-click on Add/Re move Programs to open t he Ad d/Remove Pr ograms Pr ope rties window . 4 Click Win[...]

1-4 C HAPTER 1: C ONNECTING TO Y OUR ISP 8 Insert your Windows 95/ 98 Set up diske tte or CD-ROM when you are pr ompted, and Windows 95/98 insta lls Di al-Up Net working . Step T wo: Inst alling Dial-Up T CP/IP S uppor t 1 Click Start | Settings | Co ntrol Pan el . 2 On the Contr ol Pane l, doubl e-click on the Network to dis pla y th e Network win[...]

Windows 95/98 1-5 9 On the My Con nection wi ndo w , click Ser v er T ype , and deselect the follow ing: ■ Log on to Net work ■ NetBEUI ■ IPX /SP X Compa tible[...]

1-6 C HAPTER 1: C ONNECTING TO Y OUR ISP 10 Click OK , and OK . Step Four: Custom izing th e TCP/I P Settin gs Dependi ng on the ISP you use, you may need t o customize the TCP/IP settings. Follow step s 1- 6 and if you stil l cannot connect to y our ISP contac t you can co ntact yo ur ISP fo r spec ific in format ion such as an IP addr ess or Doma[...]

Windows 95/98 1-7 5 Specif y an IP addr ess, i f needed: 6 After you sp ecify an IP A ddr ess, specify se rver assigned n ame server addr esses, i f needed: If your ISP Do this Gives you a sp ecific IP addr ess Click Specify an IP address and enter the IP address provi ded by yo ur IS P Does not give you a speci fic IP addre ss Click S erver ass ig[...]

1-8 C HAPTER 1: C ONNECTING TO Y OUR ISP 7 Double-cl ick your New Connec tion icon to conn ect! Wind ows NT 4 .0 and Later TCP/I P is t he main pr otocol use d to transfer data via the In ternet. T o use TCP/I P wit h W indows NT , you mu st connec t to your ISP usin g a PPP or SLIP conne ction. Each ISP ha s different re quirements. Before u sing [...]

Window s NT 4.0 and Later 1-9 What yo u ne ed Before you begin , ob tain the foll ow ing in for mati on : ■ Does your ISP have a SLIP or PPP account? ■ Y our ISP’ s telephone numb er ■ Does your ISP supply a static or dyn amic IP addr ess? ■ Y our ISP's primary and seco nda ry DNS servers ■ INF file for W indow s NT Con fig urin g [...]

1-10 C HAPTER 1: C ONNECTING TO Y OUR ISP 8 Click Network. 9 Select the protocols required to dial i n and out w ith yo ur Busi ness Modem. 10 Set Encryption Setting s to A llow a ny auth enticat ion incl uding cl ear text . 11 Click Conti nue to comp le te RAS setup. Determin ing if T CP/IP is i nstalle d TCP/I P must be instal led befor e you c a[...]

Window s NT 4.0 and Later 1-11 7 Sele ct Enable software comp r ession . 8 Specif y an IP addr ess by clicki ng TCP/I P sett i n g s . 9 After you sp ecify an IP A ddr ess, specify se rver assigned n ame server addr esses, i f needed : Confi guri ng a SLIP connec tion The fol low ing st eps e xplai n ho w to con fig ur e Windows NT fo r us e with a[...]

1-12 C HAPTER 1: C ONNECTING TO Y OUR ISP T r oubles hoot ing R AS RA S is signi fican tly ea sie r to troublesho ot then W in95 Dia l -Up Network ing, there a r e a finite n umber o f problem s that o ne runs into on a dail y basis, and t he major ity of these ar e c aused by misconfi guration . Most connec tion p roblems c an be solve d by follow[...]

Macint osh 1-13 System C onfigura tion Also, if you ar en’ t usi ng A ppleT alk® Remot e A ccess (ARA), set A ppl eT alk to Inac tive (in Chooser). The modem in itiali zat ion stri ng should be AT&F1&D0 . For i nstruction s abou t how to set up your Macinto sh commu nications software package, see the software installatio n instru ctio n[...]

1-14 C HAPTER 1: C ONNECTING TO Y OUR ISP the script re ceives an OK back fr om the modem and/or t he system r esponds with a pr oper speed . Configu ring O pen T rans port PPP Se lectin g the corr ect modem 1 Go to Ap ple Me nu | Co ntrol Pane ls | Mod em . 2 In the Modems Window , choose the po rt that your m ode m i s con nected to in th e Conn [...]

Macint osh 1-15 Selectin g the corr ect TCP/IP setting s 1 Go to Ap ple Me nu | Co ntrol Pane l | TCP /IP . 2 In the TCP/IP window , select PPP in the Conn ect via drop d own box. 3 Set the Config ure drop down box to Usin g PP P Server . 4 T ype in your internet servi ce provi ders Domai n Name Server A ddress( DNS) numb ers in the Name server add[...]

1-16 C HAPTER 1: C ONNECTING TO Y OUR ISP Setting up you r ISP informa tion 1 Go to Ap ple Me nu | Co ntrol Pane ls | PPP . 2 In the PPP wi ndow , select Register ed Us er . 3 T ype in your In ternet Service pr ovid ers login name an d your passwor d in the name and passwo rd bo xes. 4 Put the pho ne number that you dial to con nect to your int ern[...]

Other Operating S ystem s 1-17 Othe r Opera t ing Systems Thi s se ct io ns e xp la i ns ho w to con f ig ure your mo d em for : ■ W indows 3. x ■ MS-DO S ■ UNIX , Linux, or AIX If Y ou Are Using Wind ows 3.x Windows 3.x comes with a bui lt - in communicat ions softwar e package, Windows T erminal. Y ou can use W indows T erm ina l to test yo[...]

1-18 C HAPTER 1: C ONNECTING TO Y OUR ISP[...]

2 U SING THE AT C OMMAND S ET This chap ter includ es info rmation about ■ Basic A T commands ■ Using S- Registe rs ■ Unders tanding b it-mapped S-Reg isters Overview Y ou can use A T commands to change yo ur modem setti ng s at any time. T o send A T commands to your modem, you n eed to put your communica tions sof twar e in T erminal M ode [...]

2-2 C HAPTER 2: U SING THE AT C OMMAND S ET AT&K3X2DT5551234 Hyphens an d parentheses ad d to the cou nt of 56 charact ers but, spaces do not. Basic A T co mma nds Th e comm and A T informs the modem th at a command is co min g. A T must pr ecede all co mmands excep t A/, A> a nd ++ +. Exampl e: Send ing ATD5551234 will make t he modem dial [...]

Using S- Registers 2-3 Disp layi ng S- Regi ster settings Y ou can d ispl ay S-R egist ers i n a va riet y of ways . See the ta ble be low f or more info rmatio n. Exampl e: Send ing ATS0? , displ ays the contents or setting for S-Reg ister 0. When u sing the c ommands A TI4 and A TI5, S-Register settings appear as a table seven columns wide , each[...]

2-4 C HAPTER 2: U SING THE AT C OMMAND S ET Getting a list of S-Regis ters In orde r to issue this c omman d, you must be in T erminal Mod e. See Appendi x A, S -Register s for a comp lete list o f S-Re gisters. Understan ding bit-mappe d S-Regist ers A bit-ma pped S-Reg ister uses one num ber to descri be a co llecti on of settings. Bit-mapp ing a[...]

3 M ODES OF O PERATION This chapt er contain s informat ion about ■ Command an d Online Mode s ■ Cont rollin g L oca l Ec h o ■ Data and Fax M odes Command and Onl ine Mo de s DO NOT type AT before +++ or <ENTER> after th e command If you want to Set the modem to Use this c ommand Control the modem usin g AT commands. Command Mode +++ ([...]

3-2 C HAPTER 3: M ODES OF O PERATION Enterin g Onli ne Comma nd Mod e Whe n the modem is in Onli ne Mo de, the only c omm and it recognize s is an e scape c ode, or ++ +. Revert t o Command Mode without losi ng connect io ns by sending ATS14.0=0 to the mod em bef or e est ablishi ng your conn ection. 5 W ait one second after send ing the la st item[...]

Controllin g Loca l Echo 3-3 Cont rollin g Loc al Echo Ther e ar e two local echo setti ngs, one for Command Mo de and one fo r Onlin e Mo de. Comma nd-Mode Local E cho Y ou can configu r e your mode m to display the commands you typ e on scr een by using t he A TEn command . Althoug h you cannot see the command whe n you set A TE0, the modem is re[...]

3-4 C HAPTER 3: M ODES OF O PERATION Data and Fax Modes Once you ar e in Command Mode, you can initi alize the modem in Da ta or Fax mode. Fax op e rat ions requi re facs im i le - co mpa tib le co mm un ic a ti on s so ftw a re that can se nd or rece ive Grou p III faxes. Fo llow the in structions i n your fax softwar e manual. The modems def au l[...]

Data and F ax Mod es 3-5 If you ar e not sur e whether yo ur modem is in D ata or Fax mode, use the AT+FCLASS? c ommand . Whenever t he modem is r eset using th e A TZ command or by turn ing the power off and then o n, it will re set to Data Mode. If the modem returns a va lue of This ind icates 0 Data Mode 1 Class 1 Fax Mo de 2.0 Class 2. 0 Fax Mo[...]

3-6 C HAPTER 3: M ODES OF O PERATION[...]

4 D IALING , A NSWERING , AND H ANGI NG U P This ch apter exp lains how t o use b asic A T commands fo r: ■ Dialin g ■ Carrier loss redial ■ Answe r in g c alls ■ Makin g In ternational calls ■ Call d etection ■ Caller ID functio ns ■ Distinct ive Ri ng suppo rt Dialing Y ou can use your modem to dial the spec ified ph one number and [...]

4-2 C HAPTER 4: D IA LIN G , A NSWERING , AND H ANGING U P Wait for a n answer (w ith X3 or hi gher). Some online servi ces answer the phon e and return a tape-recorded re quest for info rmation before process ing transa ctions. Use the AT@ com mand to tell the modem to detect at least one ring, wait for five seconds o f silence a t the other e nd [...]

Carr ier Los s Re dial 4-3 Carrier Los s Re di al Y ou can se t the Bu siness M odem to redial the last-d ialed n umber a fter it loses carrier (carri er is the signal ma intained between two modems wh ile they ar e on li ne) . This fea ture i s useful fo r dialed-l i ne connecti ons that operate un attended. Exam ple: Send ing ATS44=20 sets a 20 -[...]

4-4 C HAPTER 4: D IA LIN G , A NSWERING , AND H ANGING U P Answer ing Ca ll s Y our modem can be configur ed to answer calls. By de faul t, your Busi ness Modem will not automat ically answe rs call s. For ce Answer Mode Auto Answer Y ou can set y our modem to Au to Answe r using the A TS0 command . Exampl e: Send ing ATS0=0 will not allow you r mo[...]

Making Inte rna t io na l calls 4-5 Hang ing u p If you want to end a connecti on with a r emote devi ce do the foll owing: 1 Enter Onli ne Command Mo de by typing +++ 2 W ait 1 se co n d 3 Ty p e ATH Making International calls Y ou can use the A TB n , A T&G n a nd A TP n co mmands for makin g analog internati onal calls ab ove 1200 bps. Hands[...]

4-6 C HAPTER 4: D IA LIN G , A NSWERING , AND H ANGING U P Guard tone The A T&G n command only appli es t o analog over sea s calls at 2400 or 1200 b ps. If you set &G2 yo u must also se nd ATB0 t o the modem. Thi s setting allow s the Bus iness Mod em to answe r al l cal ls fr om ove rseas . Make/Br eak Ratio The A T&P n command set s [...]

Caller I D Functions 4-7 Caller ID Fu nctio ns Caller ID is a se rvice p rovided b y loca l tele phone compa nies. When y ou subscrib e to caller I D, your phone compa ny begins pr ovid ing you real-time inform ation about incom ing c alls. The calle r ID signal in cludes the date and time of t he call, the ph one numbe r of the call ing device , a[...]

4-8 C HAPTER 4: D IA LIN G , A NSWERING , AND H ANGING U P How the Busine ss Mode m H andle s Caller I D When th e mod em receive s the ca ller ID s igna l, it stores the info rmatio n in memory . Y ou c an acce ss t he inf orm atio n at a ny time by sendi ng ATI1 5 to the mod e m. ati15 3Com OfficeConnect 56K Business Modem CID Status… 80 1E 01 [...]

Caller I D Functions 4-9 Pr esentation Fo rmats The Bus in ess M od e m s e nd s the ca lle r ID in fo rm ati o n to yo ur com pu t e r formatt ed or u nforma tted. Formatted presentati on is a transla tion o f the caller ID signal i nto ASCII text. Un formatted presentati on is a hexadecim al r epr esentation of the caller ID signal. An Exampl e o[...]

4-10 C HAPTER 4: D IALI NG , A NSWERING , AND H ANGING U P Refer ences For more info rmation about Ca lling Number D elivery (CND ), refer to Bellcor e documents TR- TSY -000030 and TR-T SY -000031. T o obtain Bellcor e documen ts, co ntact: Bellcor e Customer Ser v ice 8 Corpo rate Pl ace Room 3A18 4 Piscata way , NJ 0 8854-41 96 (800) 521-267 3 D[...]

Distinct ive R ing Supp ort 4-11 Ther e ar e four ring pa tterns in common use: These ar e graph ical de pi ctions of each ring pa ttern. Comma nds Exam ple: Send ing ATS70.0=1.3=1 to yo ur modem enables t he recogniti on of ring ty pes A and D only . Ring Description A 1.2 t o 2.0 se conds on, 4. 0 sec on ds of f . B 0.8 se cond on, 0.4 secon d of[...]

4-12 C HAPTER 4: D IALI NG , A NSWERING , AND H ANGING U P When a call come s in with a ring typ e A or D, the Business M odem wi ll send the result co de RING A or RING D, r especti vely . The Bu siness Modem will igno re other ring types. If S70 i s set to 0 (the defau lt) the Bu siness Modem det ects ring ty pes A and B, se nding the result code[...]

5 W ORKING WITH M EMORY This chapt er contain s informat ion about: ■ Saving a pho ne number to N VRAM ■ Wo rking with Flash Me mory Y ou can upgrad e the softwar e hel d in Flas h memory by perf orming a software d ownload. Se e Chapt er 3 , Upgr adi ng your Sof tware, for mor e informat ion abo ut perfo rming a software downl oads. Overview B[...]

5-2 C HAPTER 5: W ORKING WITH M EMOR Y Exampl e: Send ing ATI5 will displ ay NVRAM settin gs on your scr een. T o see a co mple te list ing of the pe rman ent setti ngs s tored in Fl ash memory see Appendix C , Flow Con trol T em plates. Working with RAM and NVRA M Y ou can change a ny setting just for the cu rrent session. For ex ample setting yo [...]

Working with Flash Memory 5-3 If the call requ ires a sp ecial setting , ins ert it in the comma nd be fore the DSn comman d. In thi s example, &M0 (no er ro r co ntro l) comes be f ore DS2. T ype : AT&M0DS2 The A T&Zn=s command f unc tions diff erently whe n Dial Secur ity is enabled . See Cha pt er 11, Dial Security , for more inf o r[...]

5-4 C HAPTER 5: W ORKING WITH M EMOR Y All of the s etting s in each template are given in A ppendix C, Flow Contr ol T emplate s . For more informatio n abo ut ha rdware and software flow control, See Chapter 12 , F l ow Co nt rol . Saving ROM T emplates to NV RAM T o save one of the th r ee RO M templat es to NVRA M and h ave it serve as the rese[...]

6 C ONTR OLLING R ESULT C ODE D ISPLAYS This chapt er contain s informat ion about: ■ Resu lt Code Displa y co mmand s ■ Additi onal Result Code subsets Result Co de Display Commands The comma nds listed bel ow contr ol whether r esult codes ar e displa yed, and in what fo r mat they ar e displa yed . If you want th e modem to Command Display r[...]

6-2 C HAPTER 6: C ON TRO LLING R ESULT C ODE D ISPLAYS Additio nal Re su lt Code Subsets ARQ ( Autom atic Repeat Req uest) is used in t his ma nual t o den ote ca lls that use error con tro l. . The numer ic identif i ers for &A3 re sult codes are t he same as those used for &A2. If you request nu meric di splay (V0) and &A3, yo u won?[...]

7 C ONTR OLLING EIA-232 S IGNALIN G This c hapter c ontains infor mation about c onfig uring the EI A-232 1 signall ing bet ween you r compu ter and modem: ■ Data T ermina l Ready ■ Data Set Re ady ■ Carrier Detect Data T e rminal Ready Y our compute r sends a Data T ermina l Ready (DT R) signal to t he Bu siness Modem when it is r eady to se[...]

7-2 C HAPTER 7: C ON TRO LLING EIA-232 S IGNALING Data Se t Ready Under nor mal conditi ons, the Bu siness Modem sends a D ata Set Ready (DSR) sign al to your comp uter when it is read y to send and r eceive dat a. CAUTION: Do not change the def ault setti ng of &S0 unle ss you know that your install ation requ ires a diff erent setti ng. Few W[...]

Carrier Detect 7-3 Carrier Dete ct Carrie r means ther e is communi cation wit h the device on th e ot her end of th e conn ection . Unde r norm al co nditio ns, th e Bus iness Mode m sen ds a Carrier D etect (CD) signal in r esponse to e stablish ing a conne ction with anothe r modem. Y ou can use the A T&C n command to contro l ho w the Busin[...]

7-4 C HAPTER 7: C ON TRO LLING EIA-232 S IGNALING[...]

8 C ONTR OLLING D ATA R ATES This chapt er contain s informat ion about ■ Serial po rt rates ■ Connec tion rate s ■ Cont r olling L ink Spe eds with &N and & U ■ Settin g DTE Ra te to 2 30 Kb ps Overview Y ou can set the B usiness M odem to u se fixed or va riable seria l port rates and fixed or variable connec tion rate s. Serial p[...]

8-2 C HAPTER 8: C ON TRO LLING D ATA R ATES Y our s oftware may u se terms su ch as locked serial p ort (fixed rate ) or autoba ud (vari able rat e). The seria l port r ate MUST b e equal to or high er than t he Conne ction ra te (&Nn). To allow your modem Set the serial port rate as Command To change its serial port rate to match the connectio[...]

Connection Rates 8- 3 Connec tion Ra tes Y o u can set the Busine ss Modem to a fixed or vari able connectio n rate for data calls. Set a varia ble rate to have the Busi ness Modem nego tiate with the remote device for the h ighest possibl e connection ra te. Set a fixed rate to connect only at a specified ra te. Y ou m ight use a fixed ra te to fi[...]

8-4 C HAPTER 8: C ON TRO LLING D ATA R ATES Controllin g Li nk Speeds with &N and &U Y ou can use the & N and &U commands t o contr ol link spe eds. Cont rollin g Li nk Speeds U se the fol lowing ta ble to det e r mine how to use &N and &U co mmands: The defau lt values for & N and &U are 0. If you change th ese valu[...]

Controlling Link Speed s with &N and &U 8-5 Limiting the Lo west Poss ib le Co nn ect Speed The &U comma nd allows you t o li mit the lowe st possible connect speed. If a r emote mo dem attemp ts to co nnect t o your Busine ss Modem a t a speed lower th an &U, your Bu sines s Mode m will not al low i t to conn ect. See the tabl e in[...]

8-6 C HAPTER 8: C ON TRO LLING D ATA R ATES &N and &U Co mmand V alues Use the fol l owing tabl e for a compl ete list of &N and &U li nk sp eeds and their associated i ndexes: Link Spe ed Index Highest 0 300 1 1200 2 2400 3 4800 4 7200 5 9600 6 12000 7 14400 8 16800 9 19200 10 21600 11 24000 12 26400 13 28800 14 31200 15 33600 16 2[...]

Setting DT E Rate to 230 Kbps 8-7 Setting DTE Ra te to 230 Kbps The DTE ra te of yo ur Bu sin ess Modem h as be en i nc r ease d to 2 30 kbp s t o enhanc e t hr oughput . This command is only suppor ted on Business Mo dems attached t o high speed serial cards. 46666 31 48000 32 49333 33 50666 34 52000 35 53333 36 54666 37 56000 38 57333 39 Link Spe[...]

8-8 C HAPTER 8: C ON TRO LLING D ATA R ATES[...]

9 A CCESSING AND C ONFIGURI NG THE B USINESS M ODEM R EMOTELY This chapt er contain s informat ion about: ■ Settin g up remo te ac cess ■ Accessing the h ost ■ Quitting a remo te access session Overview Y ou can set up the Busine ss Modem so other devices can view or change its conf ig u ra tio n remotely . Y ou should be familiar with these [...]

9-2 C HAPTER 9: A CCESSING AND C O NFIGU RING THE B USINESS M ODEM R EMOTELY 2 Enable r emote acce ss. Set R egist er S 41 for a val ue of 1 or gr e at er . S41 sets th e numb er of log -in attempts ava il abl e to the remot e user . A setti ng of zero allows no log -in attempts di sablin g remote access. Exampl e: Send ing ATS41=1&W allows for[...]

Accessing the Host 9-3 Other Remote-Access Comma nds The table below is a l ist of remo te-access confi guration comman ds. Exampl e: Send ing AT%P1= will erase th e view and change pa ssword . WARNING: If you erase the %P1 password with out disab ling remo te access (using ATS41=0 ) , anyone coul d acc ess the Business Mo dem and chan ge its c onf[...]

9-4 C HAPTER 9: A CCESSING AND C O NFIGU RING THE B USINESS M ODEM R EMOTELY 4 Y o u should see a di splay similar to this: 3Com OfficeConnect 56 K Business Modem Remote Access Session Serial Number 000000A 000000001 Password (Ctrl-C to c ancel)? Ther e i s a 3-mi nute time l imit for enteri ng t he passwor d. If the number of unsuccessful lo g-in [...]

Accessing the Host 9-5 Dependi ng on your ac cess pr ivilege s, you can use the r egular set of Business Mod em A T commands. CAUTION: Be carefu l not to send ATZ or ATZ! or you will lo se the connect ion! Remote Conf iguration Comma nds Ther e ar e special com mands that can be used only dur ing a r emote-access session. Y ou can change the host B[...]

9-6 C HAPTER 9: A CCESSING AND C O NFIGU RING THE B USINESS M ODEM R EMOTELY Y ou can use the A T%Fn command to con trol the data format . Y ou can use the A T %C n command to contr ol whether and when to app l y chan ge s t o the conf igura ti on Exampl e: Send ing AT%C1 will cancel any changes made t o the modem during a remote acce ss se ssion a[...]

Quitting a Remote-Access Se ssion 9- 7 If yo u r est or e the ori ginal co nfigurat i on using the A T%C1 command, the fir st pr ompt is r estor ed, assuri ng you the or i ginal c onfigura tion is in tact . Quit ting a Remote -Access Session If you wa nt to quit th e remote-access lo gin be fore you have enter ed the password, retur n onli ne by p [...]

9-8 C HAPTER 9: A CCESSING AND C O NFIGU RING THE B USINESS M ODEM R EMOTELY[...]

10 D IAL S ECURITY This chapt er contain s informat ion about: ■ Settin g up D ial Se curity ■ Main ta inin g securit y accounts ■ What the gu est user needs to do ■ Config uring di al security remote ly Overview Dial Secu rity is desi gned to protec t netwo rks a nd da ta cente rs from unauthor ized access. Y ou should be familiar with the[...]

10-2 C HAPTER 10 : D IAL S ECURI TY Setting up Dial Security Here is a summar y of the step s fo r setting up Di al Securi ty : ■ Set up a n account for yoursel f. ■ Identify your account as the Adm i nistra tive Accou nt. ■ Set up g uest-user accounts. ■ Enable local (ho st) securi ty . ■ Choose a Di al Securi ty metho d. ■ Enable D ia[...]

Setting up Dial Security 10-3 Dialba c k op tio ns Y ou can set the Busi ness Modem to auto mat ically di alback a c er tain number after a clien t modem dials in . Count y our commas! There sho ul d always be four com mas in the %A command. Do not inser t spaces betwee n commas or between fields and commas. Spac es will inval idate the com mand. T[...]

10-4 C HAPTER 10 : D IAL S ECURI TY will b e locked out o f the B usiness Modem’ s dial securit y featur es. Y ou will need to restor e the factory defaults. Thi s will erase ALL passwords and you will ha ve to reconfigure all your accoun ts. 3 Set up g uest-user accounts. Use the A T %A n command to set up g uest-user accounts i n the same way y[...]

Setting up Dial Security 10-5 Autopas s Prompting Autopass is the defau lt form o f password protecti on. Autop ass automate s the pr ocess of log gi ng in to th e host modem, but it re quir e s the guest and host devices to be Busi ness Modems. When a guest device attem pts an Autopa ss connecti on, the gu est inclu de s its pa ss w o rd in its V [...]

10-6 C HAPTER 10 : D IAL S ECURI TY 6 Enable D ial Securit y . WARNING: Befor e you enabl e Dial Secur ity , you must set up an administ rative acc ount and passwo rd. See Steps 1 & 2. Exampl e: Issuin g AT%A3=corn,y,y,y,5551234 to yo ur mod em will enable Passwo rd Pr ompting and Dialb ack for account 3, which has the passw ord corn . Y ou mu [...]

Maintain ing Security Accounts 10-7 Maintainin g Security Acco unts Once the administra ti ve password is set and Dial Securit y is enabled, th e administ rator i s the only one who can access account in formati on. Y ou can use the A T% S= and A T%E= commands to chan ge and modif y accoun t info rmatio n. Exampl e: Send ing AT%E=3 erases passwor d[...]

10-8 C HAPTER 10 : D IAL S ECURI TY What th e Guest User Needs to Do When guest user s want to ca ll i n to the host (assumi ng you have enabl ed Dial Securi ty by enteri ng ATS53.0=1 ), ■ They must kn ow the passwor d. ■ If you have enabled Dialb ack, they must set their devi ce to auto-ans wer . 1 If the host has se curity enab led, ge t a pa[...]

Configurin g Dial Securi ty Remotely 10-9 3 If Dialback is enabl ed at the host Business Mo dem’ s site, set your modem to answer th e host Busine ss Modem when it dial s back. 4 Call th e host. 5 After the call ends you can disabl e Auto An swer . Conf ig uring Dia l Security Rem otely The ho st admi nistrator ca n confi gure the host’ s secur[...]

10-10 C HAPTER 10 : D IAL S ECURI TY WARNING: If you do not use the A TZ command t o end a r emote -access session, Dial Security will r emain d isabled at the h ost, and anyone diali ng in to the host for re mote access will have access to the A TI10 screen and all Dial Securi ty accounts.[...]

11 F LOW C ONTR OL This chapt er contain s informat ion about ■ Hardwar e and software flow con trol ■ Received -data f low cont rol ■ T ransmi t-data f low contr ol Overview The Business M odem has two bu ffers, one for data tra nsmitted fr om your compute r , and one for data rece ived fr om the phone line. Flow contr ol pr ovides a system [...]

11-2 C HAPTER 11 : F LOW C ONTROL Hardwar e and Software Flow Control Ther e ar e two kinds of f low contr ol: ha rdwar e and software. Business Modems su pport both, bu t your compu ter and communi cations soft ware must also sup por t the kind of flow contr ol you cho ose. Hardware Flow Contr ol Busi ness M odem s im plemen t hardwa re flow con t[...]

Received Data Flow C ontrol 11-3 Received Data Flow Control Flow contr o l sett ings ar e contr oll ed by the A T&Rn and A T&In comma nds. The de fault setti ngs are &R2& I0. Use the fol lowing ta ble for m ore inform at ion ab o ut set ting th e flo w contro l. For your mo dem to Command Pause before sendi ng CTS signal a fter rece[...]

11-4 C HAPTER 11 : F LOW C ONTROL Exampl e: Send ing AT&I2 will r e move XON/ XOFF commands fr om the data str eam instead of sending them to the r emote comp ut er . This will for ce the Busin ess Modem to act of the XON/XOFF comma nds. Enable He wlett Packard-T erminal mode. App lies only to Business Mode ms attached to term inals in an HP sy[...]

Tran smit- Data F low C ontrol 11-5 T ransmit-Data Flow Control This type of flo w cont r ol is fo r data transmitte d to the Business Modem by it s attached comput er . For your mo dem to Command Disable t ransmit data flow control AT&H0 Enable Hardware flow control. Require s that your compute r and so ftware supp ort Clear to Send (CTS) at t[...]

11-6 C HAPTER 11 : F LOW C ONTROL[...]

12 H ANDSHAK ING , E RR OR C ONTR OL , D ATA C OMPR ESSION , AN D T HR OUGHPUT This chapt er contain s informat ion about: ■ Handshaking ■ Sele ctive Reje ct ■ V .90 C apabili ties ■ Error Control ■ Data comp ression ■ Getti ng maximu m thr oughp ut Handshaking W ith each call, B usin ess M odems go throug h a li nk ne gotiati on proce [...]

12-2 C HAPTER 12 : H ANDSHAKING , E RROR C ONTROL , D ATA C OMPRESSION , AND T HROUGHPUT Select i v e Re j ect is an opt io na l pa rt of th e IT U-T V .42 (L AP M) sta n da rd. Attaining Speeds Above 28.8 Kbp s V .34 connect io ns at 21.6, 24, and 26. 4 Kbps ar e common. T o get connect ions of 28.8, 31.2, and 33. 6 Kbps, li ne qu ality must be pr[...]

V.90 Capa bilities 12-3 If you en abl e the V .8 call indi cate tone , exp ect to hea r a sou nd like a fa st ringi ng signal whi l e the call is be ing connected . V. 3 4 If the remote device has V .3 4 ca pabili ty , Bu sines s Mode m use a li ne pr obin g techni que to dete rmine the high est spee d possible under curr ent line con dition s, the[...]

12-4 C HAPTER 12 : H ANDSHAKING , E RROR C ONTROL , D ATA C OMPRESSION , AND T HROUGHPUT If the r emot e devi ce has V .FC capabil ity , the Bu siness Modem uses a li ne pr obin g techni que to dete rmine the high est spee d possible under curr ent line co nd i tio ns, the n co m p le te s the con n ec ti on . If the remote an a lo g device does no[...]

Error Contro l 12-5 Lower -speed V . Pr otocol s Older , lower -speed "V ." pr otocols do not employ lin e probi ng. Inst ead they use pr edef ined answer to nes to specify or i dentify spee d capabilitie s. These pr otoco ls de fine the fo llowing maximum speeds: ■ V .3 2terbo: 19.2 Kbps, wit h an additi onal USR de vice-t o-USR dev ic[...]

12-6 C HAPTER 12 : H ANDSHAKING , E RROR C ONTROL , D ATA C OMPRESSION , AND T HROUGHPUT . Exampl e: Sendi ng AT&M4 allows your mod em to operate in Nor mal Mode is an AR Q conne ction can’ t be made. Err or con tr ol is availabl e for call s at 1200 bps and above. It can be disable d, although high-spe ed calls (9600 bp s or higher ) should [...]

Error Contro l 12-7 V .42 Err or Co nt r ol The Busin ess Mode m first tri es for a V . 42 conne ction, th en an MNP connect ion. Th e foll owing i nformat ion is based on the Business Modem's setting of &M4. This int ernatio nal standa rd includes a two -stage hand-s haking pr ocess: ■ A Dete cti on phase th at is based on an exchan ge [...]

12-8 C HAPTER 12 : H ANDSHAKING , E RROR C ONTROL , D ATA C OMPRESSION , AND T HROUGHPUT Data Comp ression Busi ness M odem s emp loy di f ferent data c ompress ion tech nique s du ring data conn ections. Exampl e: Send ing AT&K3 is used to transfer com p ressed files . The modem will only negot ia te for V .42bis compr essio n. This command al[...]

Getting M aximum Throughp ut 12-9 Possible dictiona ry sizes: Y our modem uses an 11-bi t, or 20 48 -entr y diction ary , but they can r educe it s size t o accommo date a r emote modem that use s a 9 - or 10-bit di c tio n ary . ■ Maximum string length o f each entry . As t he dictiona ry fills, yo ur modem dele tes the old est unused str ing s.[...]

12-10 C HAPTER 12 : H ANDSHAKING , E RROR C ONTROL , D ATA C OMPRESSION , AND T HROUGHPUT Installa tions with spec ial ized softwar e may want to enable a fixed serial po rt rate for ARQ calls a nd a variable serial po rt rate for non-ARQ cal ls. See the &B2 command in Append ix B, Alph abetic Command Su mmary . ■ The call i s under da ta com[...]

Getting M aximum Throughp ut 12 -11 Overhead is mini mal wit h ZMODEM, re sulting in thr oughput that is almost equal to that obtain ed with no fil e-transfer protoco l. ZMODEM should al so be used for non-ARQ connecti ons. Leav e t he Business Modem at i ts &M4 and &K1 settin gs for both err or contr ol and data compr ession. YMODEM-G is a[...]

12-12 C HAPTER 12 : H ANDSHAKING , E RROR C ONTROL , D ATA C OMPRESSION , AND T HROUGHPUT[...]

13 D ISPLAYING Q UERYING AND H ELP S CR EENS This chapt er contain s informat ion about: ■ Querying ■ Displ aying h elp T o vi ew sc reen ca pture s of the help scree ns in the fo llowing cha pter , s ee Append ix B, Alph abetic Co mmand Summa ry . Overview The Busine ss Modem ca n display informat ion such a s the curre nt setting s, pr oduct [...]

13-2 C HAPTER 13 : D ISPLAYING Q UERYING AND H ELP S CREENS Perform a test of the modem’s random-access memory (RA M) an d di s pla y eith er OK (0 ) or ER ROR (4), follo wed by OK w hen the test is comp leted. You ma y want to use this comma nd if the B usines s Modem appear s to be ma lfunctio ning. ATI2 Display the Busine ss Modem ’s banner,[...]

Displaying Help 13-3 Displaying Help The Busine ss Modem pr ov ides six hel p, or comma nd summ ary , screens: basic A T command set, ampe rsand (&) comma nd set, per cent ( %) command set , pe rce nt (%) command set, dial comman d option s (D ), S-Regi st ers (S), and t he octothorp e (#) command set. To s e e the remainde r of the scr een for[...]

13-4 C HAPTER 13 : D ISPLAYING Q UERYING AND H ELP S CREENS[...]

14 T ESTING THE C ONNECTION This chapt er contain s informat ion about: ■ T e sting the Bu siness Mode m usin g A T&T n ■ T e s tin g th e Bu sine s s Mo de m us in g S- Re g is te r 16 Overview Y our modem can pe r form di gi tal an d remo te digi tal loop back tests. Y ou can use these tests to check the operations of t he transmitter and[...]

14-2 C HAPTER 14 : T ESTING THE C ONNECTION T esting the Bu siness Modem us in g AT & T n T o perfor m digita l loopback an d re mote digi tal loop back testi ng use th e AT & T n command. Y ou can type in your own dat a during test ing or use the mod em's inte rna l test pa ttern a nd er r or detector . See the foll owing sect io ns f[...]

Testi ng the Bu siness Mod em usi ng AT&Tn 14-3 Analog Loopb ack T e sting Local loopba ck testin g checks the ope ration of the Business Mo dem transmitte r and receiver . Using A T&T1 1 Send AT&M0&N 3S14.0=0 to pr e par e the modem f or testing. This command disables er r or con t rol , fixes the conne ction ra te at 2400 bps, and[...]

14-4 C HAPTER 14 : T ESTING THE C ONNECTION If you use the S18 test ti mer , but in th e process of testi ng you issue an A TZ command, S18 reset s to zero and t he timer is di sabled. Y ou cannot store a value for S18 in NVRAM; its power -on and reset defau lt is always zero. Using A T&T8 This analo g loopback option caus es th e Business Mode[...]

Testi ng the Bu siness Mod em usi ng AT&Tn 14-5 Dig ital Lo opbac k T es ting (A T&T3 ) This test can help you lo cate a pr oblem with a r emote device or with the teleph one l ine. T he fig ure below show s the data fl ow d uring D igital Loopback ( DL) testin g. 1 Send the command AT&M0&N3S14.0=0 to the modem to pr epar e f or tes[...]

14-6 C HAPTER 14 : T ESTING THE C ONNECTION Remote Digital Loopba ck T esting (A T&T6, A T&T7) The r emote digi tal l oop back test, ver ifies the co ndition of both devices and of the ph one line. Data flow is shown in t he figur e below . Data Flow Du ring Remo te Digital Loopb ack. The r equest f or and grant i ng of r emote di gital l o[...]

Testi ng the Bu siness Mod em usi ng AT&Tn 14-7 T estin g Us ing Keyboard Data (A T&T6) 1 Send A T&M0&N3S14.0=0 to prepare the Bu siness M odem fo r testing. This command disables er r or con t rol , fixes the conne ction ra te at 2400 bps, and mak es the Business Modem r et urn to command mode when you type t he escape code ( +++ )[...]

14-8 C HAPTER 14 : T ESTING THE C ONNECTION T estin g Using a Built-in T e st Patter n (A T&T7) This test opt ion causes the mod em to perfo rm a remot e digital loopback test by se nding a built-in test patte rn. An inte rnal error detector count s any err ors and, when the test is end ed, sends the number of er rors or 000 (no errors) to the [...]

Testing the Business M odem using S-Resister 16 14-9 T estin g the Bu siness Modem us in g S-Resister 16 Regis te r S1 6 is a bi t-m a pp ed regist e r (S ee App e nd ix A, S- Reg iste rs , for instructio ns for setti ng bit-ma pped regist ers). Earli er modems re quire bi t 3 to be enab led to gr ant digi ta l loop back testing to a re mote de vic[...]

14-10 C HAPTER 14 : T ESTING THE C ONNECTION T estin g Us ing Keyboard Data (A TS16=8) 1 Send AT&M0&N 3S14.0=0 to pr e par e the Busine ss Modem for test ing. This command disables er r or con t rol , fixes the conne ction ra t e at 2400 bps, and mak es the Business Modem r etur n to comman d mode when you type t he escape code ( +++ ). 2 E[...]

Testing the Business M odem using S-Resister 16 14-11 T estin g Using a Built-in T e st Patter n (A TS16=4) The test pat tern is availabl e at all speed s. A t 300 bps, the Bu siness Modem' s serial port rate must be fixed (&B1 ) and the link rate fixed at 300 bps (&N1) . At rates over 9600 bps, just set the Business Modem for a fixed [...]

14-12 C HAPTER 14 : T ESTING THE C ONNECTION[...]

15 T R OUBLESHOOTING This chapt er explains ho w to tr oubleshoot t he Business Mod em. This chapter is divid e d into the s e sectio n s: ■ Pr oblems t hat o ccur befo re connect ing. ■ Problems that occur after connectin g. ■ What to do i f you still ha ve pro bl ems. Problems That Occur Bef ore Connec ting No response to A T For W ind ows [...]

15-2 C HAPTER 15 : T ROUBLESHOOTING ■ Make sur e that verbal result cod es (status messages) are enab led. Send the se commands to t he Bu siness Modem: ■ Review y our comm unicati ons softwar e manual to see what Carri er Detect ( CD) operati ons yo ur softwar e r equir es. Then see the chapter about Contr olling EIA -232 S ignalin g. ■ Alth[...]

Proble ms Tha t Occur Befor e Connec ting 15-3 Double characters ar e appeari ng on your monito r This is a signa l that bo t h the Busine ss Modem's local e c ho and your softwar e's loc al echo ar e on. T ype the comm and to turn of f your online echo (A TF1) or turn your communica tions softwar e's local echo of f (ref er to your [...]

15-4 C HAPTER 15 : T ROUBLESHOOTING Problems tha t Occur Afte r Connec ting Y our screen dis plays ran dom or "g arbage" cha racters Make sure that t he Busin ess Modem is set to th e same bit rate, word length , pari ty , an d num ber of Stop bits as the device to wh ich yo u are connect ing. If th e setting s ar e co rrect , the pro ble[...]

Proble ms that Occur After C onnecting 15-5 Mainfram e co mputer k eeps dropping your co nnecti on Y ou must turn of f the B usiness Modem's r esult code s and character ech o (A TQ1E0). The modem at t he mainframe also needs to be set to A TQ1E0. Bad f a xes or can' t fa x ■ Make sure the fax so ftware is set to use Class 1 fax. Refe r[...]

15-6 C HAPTER 15 : T ROUBLESHOOTING ■ If you ar e atte mpting to mak e a connecti on using HST modul ation, make sure that t he mode m at t he ot her end of th e line is HST compati ble, V .32 terb o compatib le at 14.4 Kbps, V .32 compat ible at 9600 bp s , V .2 2 bi s- com p a t ib le at 24 0 0 bp s , Be ll 212 A-c o m pa ti bl e at 1200 b ps, [...]

Proble ms that Occur After C onnecting 15-7 5 If you do r eturn the Busine ss Modem to us, pl ease follo w these pr ocedur es: a Ship th e unit, posta ge pre-pai d, in its o rigina l conta iner . I f the or igina l contai ner is not avai lable, pa ck the unit car efully in a str ong box of corrugat e d card boar d with plent y of packin g material [...]

15-8 C HAPTER 15 : T ROUBLESHOOTING[...]

16 U PGRADI NG Y OUR M OD EM This chapt er contain s informat ion about: ■ Checkin g your mo dem’ s softwar e versi on ■ Getting ne w operating sof twar e ■ Sending new software to the modem ■ If your mod em doesn’ t r esp ond Overview 3Com periodi cally r eleases upd ates and enha ncements to t he modem’ s operati ng softwar e whic h[...]

16-2 C HAPTER 16 : U PGRADING Y OUR M ODEM Check t he Su pervis or and Digital S igna l Processo r (DSP) dates f ound i n the la st two line s of the screen d ispla y . Thes e da tes wi ll dete rmine which version of th e soft ware your mode m is using. The best way to f ind out the cu rr ent shipping versio n of the modem’ s softwar e is to visi[...]

Sending New Softw are to y our modem 16-3 2 Enter AT~X! . The modem shou ld respo nd as follow s: at~x! SDL Xmodem file transfer - (Y)es (N)o (T)est > 3 Ty p e t <ENTER> to start an integri ty test of the XMD file . Y our scr een should app ear as follows: SDL Xmodem file transfer - (Y)es (N)o (T)est >t * Test Mode - Flash ROM will not [...]

16-4 C HAPTER 16 : U PGRADING Y OUR M ODEM If Y o ur M ode m Does n’ t Respon d If your modem doe sn’ t r espond af ter the flash p roce ss, its memory may be corrup ted. Fol lo w the se steps to force the new softw are to the modem. 1 Power your mod em of f. The power swit ch is in the r ear rig ht corner of the back pa nel. 2 While ho lding i[...]

A S-R EGISTERS Understan ding Bit-Mapp ed S-Regist ers A bit-ma pped S-Reg ister uses one num ber to descri be a co llecti on of settings. Bit-mapp ing allows us t o pac k a lot of in f ormation i n a small space. Bit-map ped r e giste rs ar e in the f orm of Sr .b=n, wher e r is the b it-map ped r egister ;. b is th e bit ; n is 0 (of f) or 1 (on)[...]

A-2 A PPENDIX A: S-R EGISTERS Conv erting Bi ts to Dec im al V alu e s Sta rting wit h a string of eight bits, assign each "1" bi t a value base d on its p osition. Add the valu es to come up wit h the f inal d ecimal va lue. Her e’ s an example of how bits ar e convert ed to decimal values: 0100111 1 Conv erting Decim al V alu es to Bi[...]

Using Bits A-3 Using Bi ts T ur nin g in dividua l bits on a nd off is the more di rect way to set bit-map ped S-R egisters. T o do th is, speci fy the S-Regi ster tha t you want to set an d then in dicate which bi ts you want to tur n on (1 ) or off (0). Example: ATS13.0=1.4= 1.5=1 , turns bits 0, 4, an d 5 o n for S- Regi st er 13. Using Decimal [...]

A-4 A PPENDIX A: S-R EGISTERS * Bit-m appe d registe rs hav e up t o eigh t fun ctions . S21 Break length, 10 ms 10 S22 XON character 17 S23 XOFF character 19 S24 Pulsed DSR durati on, 20 ms 150 S25 DTR recogniti on time, 10 ms 5 S26 RTS/ CTS de lay tim e, 10 ms 1 S27 Bit-mapped functio ns* 0 S28 V.32 ha ndshake ti me, 100 ms 8 S29 V.21 ha ndshake [...]

A complete list of S- Registers A-5 A complete li st of S-Regist ers . Register Default F unction S0 0 Sets the num ber of ring s on which to a nswer in Auto Answer m ode. S0=0 disa bles Auto Answe r. S0=1 enabl es Auto Answer and the Business Modem answers on the fir st ring. S1 0 Coun ts and s t ores t he num ber of ring s from an inco ming call.[...]

A-6 A PPENDIX A: S-R EGISTERS S13 0 Bit -mapp ed r egis ter . See t he be ginn ing o f th is ap pend ix fo r informa tion about setting bit-mapped re gisters. Bit Value Re sult 01 Reset when DTR drops . 12 Reverse normal A uto Answer operatio n: On incom ing RING, en ter Origin ate Mode and look for an answer tone. 24 Disable 2 50 ms pause b efore [...]

A complete list of S- Registers A-7 4 16 Disabl e MNP Leve l 4; retr ansmitti ng the larg er Leve l 4 data blocks m ay be a pr ob lem if you expe ct a gr eat number of e rrors during a call. 5 32 Set Backspace key to del ete. 6 64 Some e arlier 24 00 bps M NP modems, not made by 3Com or Microcom, were not fully compa tib le wi th the MN P proto c o[...]

A-8 A PPENDIX A: S-R EGISTERS S19 0 Sets the duration, i n minutes, for th e Inactivity Timer. The timer activate s when there is no data activity on th e R232 interfac e, and at the timeou t the Busine ss Modem hangs up. S19= 0 disable s the timer. S21 10 Sets, in 10-millisecond uni ts, the length of breaks sent from the Business Mode m to the com[...]

A complete list of S- Registers A-9 Error control handshak ing options: Sele ct the tota l valu e of bit s 4 and 5 Bit 4 Bit 5 Result 00 Complete handsha king sequ ence: V.42 Dete ction, LAPM error co ntrol, MNP. 16 0 Disa ble M NP. 0 32 Disable V .42 Dete ction and L APM. 16 32 Disable Dete ction phase, if you know that the remote Business Modem d[...]

A-10 A PPENDIX A: S -R EGISTERS 4 16 Change MR t o DSR 6 64 Disable the remote-access busy message . 7 128 Disable V .32 terbo. S38 0 Sets the durati on, i n seconds, be fore a forc e d ha ng- up a nd clearing of th e Transmit buffer wh en DTR drops durin g an ARQ call. This is pro vided to allow time fo r a remote device to acknowledge rece ipt of[...]

A complete list of S- Registers A-11 01 Dial security enabled. 12 Promptin g enabl ed. 24 Local- acces s passwo rd prot ecti on enabl ed. Enabli ng local-a ccess pa ssword protec tion disa bles the &Z n=s command (which stores up to 10 p hone num bers) b ecause st ored pho ne numb ers occup y the sam e space in NVRAM as the dialback num bers fo[...]

A-12 A PPENDIX A: S -R EGISTERS 24 Disabl e preem phasis. 38 Disabl e precod ing. 4 16 Disa ble sh aping . 5 32 Disabl e V.34+ 6 64 Disabl e V.34. 7 128 Disable V.FC. S58 0 Bit -mapp ed r egis ter . See t he be ginn ing o f th is ap pend ix fo r informa tion about setting bit-mapped re gisters. Bit Value Re sult 01 Disable x2 5 32 Enabl es/ Disabl [...]

B A LPHABETIC C OMMAND S UMMARY This appen dix contai ns an alphabe tic listi ng of the A T commands to which the modem wil l respond. Defau lt setting s are bold . Basic Co mman d Set Command F unction $ Display he lp for the Basic comm and set. +++ Esca pe code . Once y our mo dem is online w ith a nother dev ice, the only command it re cognizes [...]

B-2 A PPENDIX B: A LPHABETIC C OMMAND S UMMARY With the exception of the Dial optio ns, modems igno re any commands issued af ter D in the same command string. Bn Set h ands hakin g op tions . B1 Bell answer tone. This setti ng se lects HST modul ation , but use it o nly if the mo dem is not required to answer V.34-type cal ls. Cn Enable or disable[...]

Basic Command Set B-3 If doub le characters ap pear on th e sc reen, both the modem's l ocal echo and yo ur s of twar e' s loc a l ec h o ar e on. . ! Flash th e switchh ook (off hook 0.5 secon ds, on hook 0.5 secon ds, then off hook). Us e ! when o ther mo dems s hare t he line . L? Displa y the la st-dialed n umber. L Dial the last-dial[...]

B-4 A PPENDIX B: A LPHABETIC C OMMAND S UMMARY See Appendi x A, S-Regist ers for a listin g of all the S-R egis te r s. Kn Co ntrol the mode m clock. ATI6 displays the ti me. K0 If onl ine , di s pla y cu rrent c all du rati on. I f offl ine, disp l ay last ca ll’s durati on. K1 Display the actual tim e. Set the clock using ATI3=HH:MM :SS K1. Mn [...]

Ampersan d (&) Command Set B- 5 Ampersand (&) Command Set The serial port rate M UST be eq ual to or h igher than t he &Nn ra te. . X3 Ignore Di al To ne X4 Microsoft de faul t X7 Busine ss Mode m defaul t Z Software reset. Pressing the RESET button on the rear pane l of the modem resets th e modem to the &F0 configuration template [...]

B-6 A PPENDIX B: A LPHABETIC C OMMAND S UMMARY &C1 Normal operation s. The modem sends a CD signal when i t co nnects wi th a noth er m od em an d dr ops the CD when it d isconnects. &Dn Control how the mode m re sponds to Data Termina l Ready (DTR) signals. &D0 DTR is al ways ON (ig nored). &D1 If iss u ed be f ore con n ectin g wi[...]

Ampersan d (&) Command Set B- 7 &H1 Use hardware fl ow control. Requires that your computer and softwar e support Clear to S end (CTS) at the EIA-232 interface. &H2 Use software flow contro l. Requires that your software support XON/ XOFF si gnaling. &H3 Use both ha rdware and software flow cont rol. If you are unsure ab out wh at y[...]

B-8 A PPENDIX B: A LPHABETIC C OMMAND S UMMARY &K3 Select ive data compre ssion. Th e modem negotia tes only fo r V.42bis c ompression, and disa bles MNP Leve l 5 (MN P5) co mpres s ion. Use this setting to transfer compressed files. &Ln Line t ype. &L0 Normal. &Mn Ena ble ARQ (erro r control) protocol. Both your modem a nd the remo[...]

Ampersan d (&) Command Set B- 9 n=13 26400 bps n=14 28800 bps n=15 31200 bps n=16 33600 bps n=17 28000 bps n=18 29333 bps n=19 30666 bps n=20 32000 bps n=21 33333 bps n=22 34666 bps n=23 36000 bps n=24 37333 bps n=25 38666 bps n=26 40000 bps n=27 41333 bps n=28 42666 bps n=29 44000 bps n=30 45333 bps n=31 46666 bps n=32 48000 bps n=33 49333 bps[...]

B-10 A PPENDIX B: A LPHABETIC C OMMAND S UMMARY &R2 Enable hardwa re flow control of re ceived data. The mo dem se nds data to the com puter only upon receipt of the RTS signa l. &Sn Sen d the com puter a Data Set Re ady (DS R) signa l via th e EIA-232 inte rface. ("Data Set" is i ndustry jargon for m odem.) &S0 DSR is al ways[...]

Percen t (%) Comma nd Set B-11 If the ca ll is und er MNP5 data co mpression, d estructive br eaks cause bot h modems to reset the ir data comp ression ta bles. When transmissio n resumes, th e modems build new ta bles, and t he r esult is lower -than- normal thro ughpu t. Percent (%) Command Set &Y0 Destructive , don't send break. &Y1[...]

B-12 A PPENDIX B: A LPHABETIC C OMMAND S UMMARY We recomme nd agai nst forc in g configu ratio n changes unle ss it is absolut el y necessary . An unrel iable conn ection, or loss of connec tion, may result. %An Create and configure security accounts. %Bn Remote ly configu re a mode m's serial port rate . %B0 110 b ps %B1 300 b ps %B2 600 b ps[...]

Octothorpe (#) Command Set B-13 Octotho rpe (#) Command Set %Fn Remot ely co nfigur e anot her d evice ’s dat a form at. %F0 No parity, 8 data bits. %F1 Mark parity, 7 data bits. %F2 Odd parity, 7 data bits. %F3 Even pari ty, 7 data bits. %L= Set a lo cal-a ccess pa sswor d. %Pn= Disabl e p ass word s e curity (n =0 o r n=1) wh en no c har acte r[...]

B-14 A PPENDIX B: A LPHABETIC C OMMAND S UMMARY[...]

C F LOW C ONTR OL T EMPLATE Hard ware Fl ow Control The table bel ow li sts the Har dwar e flow c ont r ol template . T o load this templa te send AT&F1 to your modem. NVRAM Options Setting Description Handshak e opti on B0 ITU-T an swer seque nce Transmitter C1 Enabl ed Comm and mod e echo E1 En abled Onli ne loca l echo F1 Disabled Trai ning [...]

C-2 A PPENDIX C: F LO W C ONTROL T EMPLATE * Detect ed by e ach modem fr om the A T prefix of th e &W command that writes you r defaults to NVRAM . Set your so ftware to the desired word length, p arity , an d serial po rt rate defau lts before sending th e modem the A T . .. &W stri ng. Error control &M4 Nor ma l/error control Link rat[...]

Software Flow control C-3 Software Flow cont r ol The table below li sts the Softwar e flow contro l template. T o load this templa te send AT&F2 to the modem. . NVRAM Options Setting Description Handshak e opti on B0 ITU-T an swer seque nce Transmitter C1 Enabl ed Comm and mod e echo E1 En abled Onli ne loca l echo F1 Disabled Trai ning tone v[...]

C-4 A PPENDIX C: F LO W C ONTROL T EMPLATE * Detect ed by e ach modem fr om the A T prefix of th e &W command that writes you r defaults to NVRAM . Set your so ftware to the desired word length, p arity , an d serial po rt rate defau lts before sending th e modem the A T . .. &W stri ng. No Flow Cont rol The table bel ow lists the No flow c[...]

No Flow Contro l C-5 * Detect ed by e ach modem fr om the A T prefix of th e &W command that writes you r defaults to NVRAM . Set your so ftware to the desired word length, p arity , an d serial po rt rate defau lts before sending th e modem the A T . .. &W stri ng. Record data software flow control &I 0 Disabled Analog d ata compressio[...]

C-6 A PPENDIX C: F LO W C ONTROL T EMPLATE[...]

D R ESULT C ODE M EANINGS AND S ETS Resul t Code Meanings Result Code Mean ing 0/OK Com mand ha s been exe cuted . 1/CONNECT Connectio n with another device. 2/RI NG Inco ming r in g det ected. 3/NO CARRIER Carrier Detect h as failed, or carrie r has been dropp ed due to dis connect. 4/ERR OR Command i s inva lid. 5/CONNECT 1200 Connectio n at repo[...]

D-2 A PPENDIX D: R ESULT C ODE M EANINGS AND S ETS Resu lt C odes Set s for X n Va l u e s Res ult C o des X0 X1 X2 X3 X4 X5 X6 X7 0/OK ❷❷❷❷❷❷❷❷ 1/CONNECT ❷❷❷❷❷❷❷❷ 2/R ING ❷❷❷❷❷❷❷❷ 3/NO CARRIER ❷❷❷❷❷❷❷❷ 4/ERR OR ❷❷❷❷❷❷❷❷ 5/CONNECT 1200 ❷❷❷❷❷❷❷ 6/NO DIAL TO[...]

E T ECHNICAL I NFORMATION T ech nical Specificatio ns Y our modem uses multi ple standa rd da ta communi cations pr otoco ls and is a lso compa tible wit h many nonstandar d sc hemes. The fo llowing schemes ar e suppor t ed: Modula tion This mo dulation Supports V.90 IT U 56K st andar d, s erver capab ilit ies. V .90 anal og clients can call int o [...]

E-2 A PPENDIX E: T ECHNICAL I NFORMATION Error Control, Data Compress io n, T esti ng, and Di aling Fax Y our Business Modem pr ovid es Grou p III - com pati bility when contr oll ed by Class 1 or Cl ass 2.0 fax soft ware. In additio n, your Busin ess Modem adhe res to the fo llow ing s tandards: ITU-T V.23 1200 bps asym metrical with 75 bps back c[...]

Techni cal S pecif ica tion s E-3 Addition al Spec ificatio ns Serial Ports Most computers provide a DB-25 or DB- 9 port t hat con form s to th e EIA-232 standar d. If you ar e connecting your Busi ness Modem to a Macint osh computer , see the section For Macint osh Computers. This featu re Supports Supporte d serial port rates 230400 , 11520 0, 57[...]

E-4 A PPENDIX E: T ECHNICAL I NFORMATION The EIA-232 Interface Y our mod em’ s serial p ort is factory set to sign al according to the EIA-232 standar d . See Fi gur e A-1, Signals at you r Business Mod em' s Serial Port . Wiring a DB-25 to DB- 9 Cabl e DB-9 conne ctors for P Cs shou ld be wir ed at the com puter end of th e cable a s shown [...]

Techni cal S pecif ica tion s E-5 Flo w Contr ol Requiremen ts If your computer an d softwar e support Cl ear to S end and you wish to use T ransmi t Data har dwar e flow cont r ol (&H1), P in 5 (DB -2 5) or Pi n 8 (DB-9) is required. If your comp uter and sof tware sup port Request to Send and you wish to use Recei ved Data hard ware flow cont[...]

E-6 A PPENDIX E: T ECHNICAL I NFORMATION Serial Ports (Ma cinto sh mode m ) These are th e sig nals gener ated or accept ed by your mod em’ s serial port:[...]

F ASCII C HART Dec Hex Cha r Dec Hex Cha r Dec Hex Cha r Dec Hex Cha r 00 00 NUL 32 20 SP 64 40 @ 96 60 ` 01 01 SOH 33 21 ! 65 41 A 97 61 a 02 02 STX 34 22 "66 42 B 98 62 b 03 03 ETX 35 23 # 67 43 C 99 63 c 04 04 EOT 36 24 $ 68 44 D 100 64 d 05 05 ENQ 37 25 % 69 45 E 101 65 e 06 06 ACK 38 26 & 70 46 F 102 66 f 07 07 BEL 39 27 ë 71 47 G 10[...]

F-2 A PPENDIX F: ASCII C HART 24 18 CAN 56 38 8 88 58 X 120 78 x 25 19 EM 57 39 9 89 59 Y 121 79 y 26 1A SUB 58 3A : 90 5A Z 122 7A z 27 1B ESC 59 3B ; 91 5B [ 123 7B { 28 1C FS 60 3C < 92 5C 124 7C | 29 1D GS 61 3D = 93 5D ] 125 7D } 30 1E RS 62 3E > 94 5E à 126 7E ~ 31 1F US 63 3F ? 95 5F _ 12 7 7F DEL Dec Hex Cha r Dec Hex Cha r Dec Hex[...]

G F AX I NFORMATION FOR P R O GRAMMERS Fax Service Class 1 Commands F AX Se r vic e Cl ass 2.0 Comm ands In additi on to the stan dar d Class 2.0 fax com mands, 3Com i mplement s the fo llowing optio nal Class 2 .0 fa x comma nds: +FCLASS? What mode is in use D ata or Fax? +FCLASS=n (0,1 ,2.0 ) Class identificatio n and control . +FCLASS=? What Fax[...]

G-2 A PPENDIX G: F AX I NFORMATION FOR P ROGRAMMERS Fax Mode Flow Cont rol Settin g Many facsimil e softwar e pr oducts use softwar e flow cont r ol when the modem is in Fax mo de. Thr oughou t our documen tation, we r ecommend that you u se hardware flow control for Data mode (factory set ting). However , to allow compatib ility with software pr o[...]

H V IEWING LED S This appen dix expl ains how to vi ew the twelve LEDs on the fr ont of your Business Modem. This LE D Status Means your Busi ness Modem Alert On Has detected a firm ware dowload error Flashi ng Firmware update i n progres s Off Normal operation Power On Is s witche d o n Off is s witc hed off Fax On Is curre nt ly co nf igur ed fo [...]

H-2 A PPENDIX H: V IEWING LED S TR On RS232 mo de: has detect ed DTR signa l USB mode: has detected successful USB re gistration Off RS232 mo de: has not detected DTR USB mo de: has not detected successful USB registratio n CD On Has detected a carrier from a remote device or carrier detect has been forced on Off Has not detected a carri er RS On H[...]

I S-R EGISTERS S-Regist ers S-Regi st ers: Thei r Fu nctions and De fault Se t tings Register Default F unction S0 0 Sets the num ber of ring s on which to a nswer in Auto Answer m ode. S0=0 di sables Auto Answe r. S0=1 enable s Auto Answer and the Business Modem answers on the fir st ring. S1 0 Coun ts and s t ores t he num ber of ring s from an i[...]

I-2 A PPENDIX I: S-R EGISTERS Register Default F unction S10 7 Sets the dura tion, in te nths of a s econd, tha t the Bus iness Modem waits afte r loss of c arrier before hanging up. This guar d time a llows the Bu sine ss Mod em to di sting uish betwe en a li ne hit , or ot her di stur banc e t hat mo menta rily breaks the conne ction, from a true[...]

S-Regi sters I-3 S15 0 Bit-mapped register. ( See Chapter 1, Usi ng the AT Command Set, for instructions about how to set bit-mapped re gisters.) Bit Value Re sult 0 1 Disable th e Busi ness Mode m's ex tra high-freque ncy equalization if it causes problem s on short er-link c alls (for H ST modu lati on on l y). 1 2 Dis a b le on li ne fal lb[...]

I-4 A PPENDIX I: S-R EGISTERS S16 0 Bit-mapped register. ( See Chapter 1, Usi ng the AT Command S et, for instructi ons on settin g bit-mapped registers.) For testing, see Chapte r 14, Testing. Bit Value Re sult 2 4 Test pattern. 3 8 Remote di gital loo pback. S18 0 Test timer for software-initi ated loopba ck testing (&Tn); disabled when S18 i[...]

S-Regi sters I-5 Bit Value Re sult 3 8 Disable 21 00 Hz an swer tone to allo w two V.42 de vices to connect more quick ly. 4 16 See ne xt page . 5 32 See ne xt page . 7 128 Unus ual soft ware incom patib ility. Some sof t ware m ay not acce pt some result code s. This setting di sables the codes a nd disp lays the 9 600 code inst ead. Th e call&apo[...]

I-6 A PPENDIX I: S-R EGISTERS Bit Value Re sult 1 2 Disable th e Busi ness Mode m's enhance d, propr ietary V.32b is modula tion. Used for troubles hooting. 2 4 Disable the faster retrai ns that occur during p roprietary V.3 2terbo modula tion. Used for troubles hooting. 3 8 Enable V.2 3. Requi red for so me British connec tions. 6 64 Disable [...]

S-Regi sters I-7 Bit Value Re sult S53 126 Bit-mapped register. (Se e Chapter 1, Using th e AT Command Set, for instructions about how to set bit-mapped re gisters.) 0 1 Enable dial security. 1 2 Enabl e autopa ss fallba ck. 2 4 Enale local -access pas sword protecti on. Enabli ng loc a l-a cce ss pas sw ord protecti on disable s the &Zn=s comm[...]

I-8 A PPENDIX I: S-R EGISTERS S56 0 Bit-mapped registe r primaril y used by 3Com Techni cal Support fo r debuggi ng purpose s. Bit Value Re sult 0 1 Disable n on-lin ear codi ng. 1 2 Disab le TX le vel de vi ation . 2 4 Disable p reem phasis. 3 8 Disable p recod ing. 4 16 Disa ble sh aping . 5 32 Disable V .34+. 6 64 Disabl e V.34. 7 128 Disable V.[...]

J W ARRAN TY 3COM CORPOR A TION LIMITED W ARRANTY 3Com Office Connect 56K Bu sine ss Mode m 3C om war rants this hardware pr oduct to be f ree from defects in workmansh ip and mater ials , un der norm al use and ser v ice, fo r the lifet i me of the pr oduct fr om the dat e of pur chase fr om 3Com or it s authori zed r eseller . 3Com's sol e o[...]

J-2 A PPENDIX J: W ARRANTY data on an d after Ja nuary 1, 2000, and Customer not i fies 3Com b efore the l a t er of Ap ril 1, 2 000, or ni nety ( 90 ) days a fter pu r ch ase of the product from 3Com or its au th or ized reselle r , 3Co m sha l l, at its option and expense, pr ovide a softwar e update which would ef fect the proper perfor mance of[...]

3COM CO RPORATION LIMITE D WARRANTY J-3 OF LA W , ST A TUTOR Y OR OTHERWISE, IN CLUDING W ARRANTIES , TERMS, OR CONDITIONS OF MER CH ANT AB ILI TY , FITNE S S FOR A P ARTIC ULAR PURPOSE, SA TIS F ACTORY QUALITY , CORRESP OND EN CE WITH DESCRIPTION , AND NON- INFRINGEMENT , ALL OF WH ICH ARE EX PRESSL Y DISCLAIM ED. 3C OM NEITH ER ASSU MES NO R AUTH[...]

J-4 A PPENDIX J: W ARRANTY GOVERNING L A W: This Limit ed W arra nty shall be governed by the laws of th e State of Ca lifor nia , U.S.A . exc luding its co nflicts of la ws p rinci ples and excludi ng the Uni ted Nations Conventio n on Con tracts for the Internati onal Sale of Goods. Importa nt: If yo u send your unit, p ack it secu rely an d be s[...]

FCC Notice: Ra dio and Te levision In terference J-5 FCC Noti ce: Ra dio and T elev isio n Interference This equip ment has been tested and found to comply wit h the limits fo r a Class B digi tal de vice, p ursuan t to Part 15 of th e FCC Rules . These limi ts ar e de signed to pr ovide reason able pr otecti on against harmfu l inte rference in a [...]

J-6 A PPENDIX J: W ARRANTY IC (Indus try Can ada) This digital appara tu s does not exceed the Class B li mi ts for radi o noise emission s from digi tal appa ratus set o ut in t he interference -causing equipm ent standa r d entitled D igital Appa ratus, IC ES-003 of Indu stry Canada. The Indu stry Canad a label iden tifies cert ified equip ment. [...]

G LOSSARY 16550 UAR T The fastest type of UART that is currently availab le. Adaptive Spee d Leve ling (AS L) Business Modem V .32 bis and V .32 terbo modems d etect improv ed li ne condit ions and shift upwar d again to the next hig her speed. The modems at both ends of the connect ion adapt in dependent ly , each detec ting a nd ad justi ng to l [...]

2 G LOSSARY dyna mically reverse the c hannels during a call if the volume o f data transfer chan ges. async hronous transmission Data tra nsmission in which the length of time between tr ansmitted characters may vary . Because the time lapses b etween transm itted characte rs are not unifo rm, the re ceivin g modem must be signal ed as to when the[...]

G LOSSARY 3 copies o f transmit ted frame s until they ar e posi tively ackn owledged by the r eceiving modem. byte A gro up of binary digit s stor ed and opera ted upon as a uni t. A byt e may ha ve a coded v alue equa l to a ch aracter in the ASCII code (letter s, number s), or h ave some other v alue mean ingful t o the computer . In user do cum[...]

4 G LOSSARY Class 1/EIA-57 8 An American sta ndar d used betwee n facsimi le appl icatio n pr ograms and facsimil e modems for sending an d rece iving Class 1 faxes. Class 2.0/E IA-592 An Amer ican sta ndar d used betwee n facsimi le appli cation pr ograms and fa csimi le mo dems f or se nding and rec eiving Class 2.0 fa xes. CO See centra l office[...]

G LOSSARY 5 data mode The mo de in which the fax mod em is cap able of sendi ng and r ecei ving data f iles. A standard modem withou t fax cap abilitie s is always i n Data mode. data set Anothe r way of sayi ng "mo dem." data terminal equipme nt (DTE) The d evice tha t genera tes or is the fina l destina tion of data. DCE See data com mu[...]

6 G LOSSARY error con trol V a rious tech nique s which che ck the reliabil ity of charac ters ( parity ) or blocks o f data. V .42, MNP and HST erro r contr ol pr otocols use err or detecti on (CRC) and r etra nsmission of e rror ed frames (ARQ). exp ansio n bus A series of slots inside a comp uter that allow for adding featur e car ds. facsimile [...]

G LOSSARY 7 HDLC See High Level Data Lin k Contro l. High Spee d T e chnolo gy (HST ) 3Com ' proprie tary si gnalin g sc heme, desi gn an d error co ntrol protoc ol for high-sp eed modems. HST i ncorpor ates t r ellis -coded m odulati on, for greater immuni ty from varia ble p hone line co ndition s, and asymm etrical modulat ion for mor e ef [...]

8 G LOSSARY loca l echo A mo dem feat ure that enables th e modem t o send co pies of key-boar d commands and t ransmitt ed data to the scr een. Wh en the modem is i n Command mod e (not onl ine to anot her syste m) the local echo is invoked thro ugh the A TE1 command. The command causes the modem to displ ay your typed comm ands. When t he modem i[...]

G LOSSARY 9 originate mode A state in which the mode m transmi ts at the p r edefin ed low frequency of the c ommunicat ions chann el and r eceives at the hi gh fr equen cy . The trans mit/r eceive f re quencies a re the r everse of the ca lled mod em which is in Answ er mod e. paralle l transmiss ion The tr ansfer of data characte rs using p arall[...]

10 G LOSSARY Read -Only Me mory (ROM ) Permanent memory , not user -progr ammable. The Business Mode m's factory set tings a re stored in ROM . re m ot e a c ce s s A featur e that allows a remo tely-loca ted user to view the Busin ess Mode m's c onf igurati on sc reens a nd c hange the Bus iness Mode m's confi guration . Passwor d p[...]

G LOSSARY 11 stop bi t The signalin g bit attach ed to the end of each cha racter bef ore characte rs are transmitte d duri ng Asynch ronous T ransm ission. shun t A small, pl astic -and-m etal pi ece use d to cover s ections of pins on a jumper . The shun t inter connects certai n pins which , dependi ng on the way the shunt is placed, de termin e[...]

12 G LOSSARY V. 1 7 An ITU-T stand ard fo r facsimile operations t hat specifi es modulati on at 14.4 Kb ps, wit h fallba ck to 12 Kbps . V .21-Fax An ITU-T sta ndard for facs imile o peratio ns at 30 0 bps. 3C om or compatibl e fax devices then tran smit or r eceive at high er speeds. V .21-Modem An IT U-T standar d for modem communicati ons at 30[...]

G LOSSARY 13 speed when li ne qualit y is impair ed, and fa ll back furthe r as necessary . They fall fo rward to the ne xt hi gher sp eed w hen line q uality improves. V .32 terbo Modulat ion scheme t hat extends the V .32 connect ion rang e: 4800, 7200, 96 00, 12K, 14.4K, 16. 8K, 19.2K , and 21.6 Kb ps. V .32 terbo modems fal l back to the next l[...]

14 G LOSSARY[...]