3Com 4210 PWR 26-PORT manual

3Com ® Switch 4210 Family Getting Started Switch 4210 PWR 9-Port Switch 4210 PWR 18-Port Switch 4210 PWR 26-Port Switch 4210 9-Port Switch 4210 18-Port Switch 4210 26-Port Switch 4210 52-Port www.3Com.com Part Number: 10016119 Rev. AB Published: J anuary, 2008[...]

3Com Corporation 350 Campus Drive Marlbor ough, MA USA 01752-3064 Copyright © 2006-2008, 3Com Corporation . All rights reserved . No part of this documentati on may be rep roduced in an y form or by any means or used to make any derivative work ( such as translation, transforma tion, or adaptation) without written permissio n from 3Com Corporat io[...]

C ONTENTS A BOUT T HIS G UIDE Download the Latest Software and Do cumentation for Y our 3Com Switch 5 Before Y ou Start 5 Related Docume ntation 6 1 P RODUCT I NTR ODUCTION Overview 7 Intr oduction to the Swit ch 4210 Family PWR Switches 8 Intr oduction to the Swit ch 4210 Family Non-PWR Models 14 T echnical Specifications 19 SFP Modules Supporte d[...]

A P IN - OUTS Null Modem Cable 57 PC-A T Serial Cable 57 Modem Cable 58 Ethernet Port RJ-45 Pin Assignm ents 58 B O BTAINING S UPPORT FOR Y OUR 3C OM P R ODUCTS Register Y our Product to Gain Service Benefits 59 Solve Problems Online 59 Purc hase Extend ed W ar ranty and Pr ofe ssional Se rvices 59 Access Softwa re Downloads 59 Contact Us 60 C 3C O[...]

A BOUT T HIS G UIDE Download the Latest Softwar e and Documentation for Y our 3Com Switch Thank you for purchasing a 3Com Switch 4210. As part of our commitment to bringing you the mos t capable and depe ndable network eq uipment, 3Com offers free softwar e maintenance updates and documentatio n updates on our website. T o obtain the mo st up-to-da[...]

6 ● 3Com Switch 4210 F amily Command Reference Related Documentation In addition to this guide, the Switch 4210 documentatio n set includes the following: ■ 3Com Switch 4210 Family Configuration Guide This guide contains information on the f eatures supported by your switch and how they can be used to optimize your network. It is supplied in PD[...]

1 P R ODUCT I NTR ODUCTION Overview The 3Com Switch 4210 Family provides high-performance, high-density , easy-to-install, NMS-manageable intellig ent Ethernet switches that support wire-speed Layer 2 switching. Three of the Switch 4210 Family models support industry standard IEEE 802.3af Power over Ether net (PoE). Figure 1 displays these models a[...]

8 C HAPTER 1: P RODUCT I NTRODUCTION Introduction to the Switch 4210 Family PWR Switches Switch 4210 9-port PWR Front panel Each Switch 4210 9-por t PWR unit provides eight 10/100Base- TX autosensing Ethern et ports, one 10/100/1000Base-T Ether net port, one 100/1000Base SFP ports, and one Console port. The SFP por t and the 10/100/1 000BASE-T Ethe[...]

Introduction to the Switch 4210 Family PW R Switches 9 Rear panel Figure 4 The Switch 4210 9-port PWR model’ s r ear panel Side panel Each Switch 4210 9-port PWR provides a security slot thr ough which you can lock the device together with an irremovable objec t to prevent theft. The security slot is located on the left side panel, as shown in Fi[...]

10 C HAPTER 1: P RODUCT I NTRODUCTION Figure 5 Fr ont panel of a Switch 4210 18-port PWR Rear panel Figure 6 Rear panel of a Switch 4210 18-port PWR Side panel Each Switch 4210 18-po rt PWR provides a security slot, through which you can lock the device together with an irremova ble object to prevent theft. The security slot is located on the left [...]

Introduction to the Switch 4210 Family PW R Switches 11 Figure 7 Secu rity slot on left side pane l of a Switch 4210 18-port PWR n If the left screw hole above the security sl ot is used, the security slot cannot be used. Power system Switch 4210 18-port PWR units support AC input. ■ Rated V oltage Range: 100 V AC to 240 V AC, 50 Hz/60 Hz ■ Inp[...]

12 C HAPTER 1: P RODUCT I NTRODUCTION Figure 8 The Switch 4210 26-port PWR model’ s front panel Rear panel Figure 9 Rear panel of a Switch 4210 26-port PWR Power system Switch 4210 26-port PWR units support AC input or DC input. ■ AC input ■ Rated voltage range: 100 V AC to 240 V AC, 50 Hz/60 Hz ■ Input voltage range: 90 V AC to 264 V AC, 4[...]

Introduction to the Switch 4210 Family PW R Switches 13 The Switch 4210 PWR Front Panel LEDs Power LED T able 3 describes the power LED on the Switch 4210 PWR model. 10/100BASE-TX Autosensing Ether net Port Status LED There ar e two port status LEDs on both side s (yellow LED on the left and green LED on the rig ht) of the 10/1 00BASE-TX Eth ernet [...]

14 C HAPTER 1: P RODUCT I NTRODUCTION Introduction to the Switch 4210 Family Non-PWR Models This section describes each Switch 4210 Family model. Switch 4210 9-port Front panel The Switch 4210 9-port model provid es eight 10/100Base-TX autosensing Ethern et ports, one 10/100/1000Base-T autosensing Ethernet port, one 100/1000Base-X SFP port, and one[...]

Introduction to the Switch 4210 Family No n-PWR Models 15 Rear panel Figure 11 The Switch 4210 9-port model’ s rear panel Power system The Switch 4210 9-por t model support s AC input. ■ Rated V oltage Range: 100 V AC to 240 V AC, 50 Hz/60 Hz ■ Input voltage range: 90 V AC to 264 V AC, 47 Hz to 63 Hz Cooling system The Switch 4210 cools off n[...]

16 C HAPTER 1: P RODUCT I NTRODUCTION Rear panel Figure 13 The Switch 4210 18-port model’ s rear panel Power system The Switch 4210 18-port model’ s support AC input. ■ Rated V o ltage Range: 100 V AC to 240 V AC, 50 Hz/60 Hz ■ Input voltage range: 90 V AC to 264 V AC, 47 Hz to 63 Hz Cooling system 3Com Switch 4210 non-PWR models cool natur[...]

Introduction to the Switch 4210 Family No n-PWR Models 17 Rear panel Figure 15 The Switch 4210 26-port r ear panel Power system The Switch 4210 26-port model supports AC in put. ■ Rated V oltage Range: 100 V AC to 240 V AC, 50 Hz/60 Hz ■ Input voltage range: 90 V AC to 264 V AC, 47 Hz to 63 Hz Cooling system 3Com Switch 4210 non-PWR models cool[...]

18 C HAPTER 1: P RODUCT I NTRODUCTION Switch 4210 Family Front Panel LEDs Power LED T able 6 describes the power LED on the Switch 4210. Port LED T able 7 describes the 10 /100Base-TX autosensing po rt’ s Link/Act LED. T able 8 describes the Speed LED o n the 10/100Base-TX port. For a description of the Link/Act LED of the Combo port, see T able [...]

Technical Specifications 19 T e chnical Specifications Ta b l e 1 0 T echnical specifications for the Switch 4210 Model Switch 4 210 52-port Switch 4210 26-port Switch 4210 18-port Switch 4210 9-port Physical dimensions (H × W × D) 43.6 x 440 x 225 mm (1.7 x 17.3 x 8.8 in.) 43.6 × 440 × 160 mm (1.7 × 17.3 × 6.3 in.) 43.6 × 360 × 160 mm (1.7[...]

20 C HAPTER 1: P RODUCT I NTRODUCTION n The Switch 4210 26-port, 18-port, and 9-port PWR mo dels provide an over -te mperature pro tection mechanism. W hen the interna l temperature e xceeds 65 ° C (149 ° F), they will stop providing power from all ports. When the temperature is below 60 ° C (140 ° F), they will continue to provide power from a[...]

SFP Modules Supported for the Switch 4210 21 SFP Modules Supported for the Switch 4210 The Switch 4210’ s front panel pr ovides one or two 1000 Mbps SFP ports in which you can plug small form-factor (SFP) modules, which are described in T able 12. n ■ The types of SFP modules may vary ov er time. Consult 3Com’ s marketing personnel or technic[...]

22 C HAPTER 1: P RODUCT I NTRODUCTION[...]

2 I NSTALLING THE S WITCH This section contains information that you need to install and set up your 3Com ® switch. For information on upgr ading your switch, refer to the Switch 4210 Release Notes availa ble at www .3Com.com. WAR N IN G: Safety Information. Before you install or remove any components from the Switch or carr y out any main tenance[...]

24 C HAPTER 2: I NSTALLING THE S WITCH AT T E N T I O N : le fait d’ouvrir le commutateur ou d’ altérer la vignet te de garantie pourrait rendre la garantie nulle. WARNUNG: Öffnen des Switches oder Manipulat ion des Garantieaufklebers kann das Erlöschen der Garantie zur Folge haben. PRECAUCIÓN: si se abre el conmutado r o se ma nipula el ad[...]

Rack-Mounting the Swi tch 25 Figure 17 Installing the switch in a 19-inch rack Mounting the fr ont bracket Mount the front bracket as shown in Figure 18 and Figure 19. Figure 18 Mount the fr ont bracket to the device Figure 19 Mount the fr ont bracket to the mount angel of the rack Mounting the rear bracket The Switch 4210 26-Port does not need rea[...]

26 C HAPTER 2: I NSTALLING THE S WITCH Figure 20 Positions for scr ew mounting on the switch Follow the steps below to mount the rear bracket: 1 Use screws to fix the r ear bracket to the re ar mount angle. 2 Determine the position for screw mounting on the switch according to the position of th e mount angle . 3 Mount the screw to the switch and m[...]

Mounting the Switch on a Desktop 27 Figure 22 Installation completed 2 Mounting the Switch on a Desktop In many cases, standar d 19-inch ra cks ar e not available. Ther efore, swi tches ar e often plac ed on a desktop. T o place yo ur sw itch on a desktop, you simply need to: ■ Make sur e that the surface is clean, flat, and sturdy . ■ Makes su[...]

28 C HAPTER 2: I NSTALLING THE S WITCH T able 13 PWR LED Colors If ther e is evidence of a pr oblem, se e “Solving Pr oblems Indicated by LEDs” on page 52 for a list of suggested solutions. CAUTION: Th e Switch has no ON/OFF switch; the only method of connecting or disconnecting mains power is by connec ting or disconnectin g the power cord. Co[...]

Connecting a Redundant Power Supply 29 WAR N IN G: When po wering any Switch 4210 fro m an RPS, make sure that the unit is earthed (grounded) by either connectin g the power cord to the unit or by connecting the earth terminal on the rear of the unit to a reliable electrical earth (or by connecting both). Ensure that th e earth connection is made b[...]

30 C HAPTER 2: I NSTALLING THE S WITCH 1500W rectifiers can provide up to 4500W . Hot removal or insertion of a rectifier does not affect the -48V DC output voltage. T able 14 shows an example of the tota l power available from several 1500W rectifiers. A minimum of two rectifiers are required for each shelf to provide N+1 rectifier redundancy . T [...]

Connecting a Redundant Power Supply 31 Figure 23 shows how to connect the power supply to the RPS socket in the back of the switch. Use the cable tie supplied with your switch to support the cable in the back of the RPS con nector as shown in Figure 23. Figure 23 RPS Connection to the Switch When the RPS is connect ed to the switch, you can move th[...]

32 C HAPTER 2: I NSTALLING THE S WITCH power requir ed to the device, pr oviding that the total power budget for the switch is not exceeded. A PoE switch combines the fun ctionality of a standard Ethernet switch with a single power supply t hat can power multi ple devices. Using a PoE swi tch has the following advantages over an non-powered network[...]

Connecting the Conso le Cable 33 When you want to use the termin al to configure the switch, follow t hese steps to connect a terminal device to y our swit ch using console cables: 1 Plug the DB-9 female connector of the Cons ole cable to the serial port of the PC or terminal where the switch is to be configured. 2 Connect the RJ-45 connector of th[...]

34 C HAPTER 2: I NSTALLING THE S WITCH[...]

3 M ANAGING YOUR S WITCH T o make full use of the features of fe red by your switch, and to change and monitor the way it wo rks, you have to access the man agement software that resides on the switch. Managing the switch can help you to impr ove its ef ficiency and therefor e the overall performance of your network. This chapter explains the initi[...]

36 C HAPTER 3: M ANAGING YOUR S WITCH Methods of Managing a Switch T o manage your switch you can use one of the following methods: ■ Command line inte rface management ■ Command line interface management using SSH ■ Web interface management ■ SNMP management Command Line Interface Manageme nt Each switch has a command line interface (CLI) [...]

Setting Up Your Switch 37 Figure 27 W eb Interface Management over the Network Refer to “Setting Up Web In terface Management” on page 48. SNMP Management Y ou can manage a switch using an y network mana gement wor kstation runn ing the Simple Network Management Protocol (SNMP) as shown in Figure 28. For a description of 3Com netw ork managemen[...]

38 C HAPTER 3: M ANAGING YOUR S WITCH Figure 29 Initial Switch Setu p and Management Flow Diagram CAUTION: T o protect your swit ch from unauthor ized access, you must change all three default passwords as soon as possible, even if you do not intend to actively manage your switch. For mo re information on default users and changing default password[...]

Setting Up Your Switch 39 dependent on a DHCP or BootP server , and eliminates the risk of the IP address changing. T o manually enter IP information for your switch, refer to “Manually Configuring IP Information” on page 42. Automatically Configur ing the IP Address using DHCP By default the switch attempts to obtain an IP address from a DHCP [...]

40 C HAPTER 3: M ANAGING YOUR S WITCH Viewing Automaticall y Configured IP Information If you allow the switch to automatically config ure its own IP information you need to discover and view the IP informatio n before you can begin to manage the switch. Y ou can discover the IP information by: ■ Connecting a workstation to the switch’ s consol[...]

Viewing Automatically Configured IP Information 41 Figure 30 User View Login 4 Enter display ip interface br to view a summary of allocated IP addresses. The initial set up of your switch is now complete and and you can now set up a management method. See “Meth ods of Man aging a Switch ” on pa ge 36 for details. If you do not intend to use the[...]

42 C HAPTER 3: M ANAGING YOUR S WITCH Manually Configuring IP Information Y ou can manually config ure the switch IP information by: ■ Connecting a workstation to the switch’ s console port using a conso le cable. Y ou can then manually enter the IP info rmation using the command line interface (CLI). This is the on ly way to assign an IP addre[...]

Manually Configuring IP Information 43 2 Open your terminal emulation software and configur e the COM port settings to which you have connected the ca ble. The settings mu st be set to match the default settings for the switch, which are: ■ 19,200 baud (bits per second) ■ 8 data bits ■ no parity ■ 1 stop bit ■ no h ard w are f l ow c o nt[...]

44 C HAPTER 3: M ANAGING YOUR S WITCH Press ENTER to get started. Login authentication Username:admin Password: <4210> %Apr 1 23:57:15:490 2000 4210 SHE LL/5/LOGIN:- 1 - admin(aux0) in unit1 login <4210> 3 Enter the system-view command and press Enter . The [4210] prompt is displayed. 4 Enter interface vlan 1 and press Enter . 5 Enter t[...]

Manually Configuring IP Information 45 ■ A suitable Web br owser . Refer to “Choosing a Browser”on page 48. ■ Existing IP address of the switch. ■ The switch’ s IP information, including the: ■ IP address ■ subnet mask ■ default gateway ■ management VLAN ID, norma lly set to the default value (1) Connecting the Workstation to th[...]

46 C HAPTER 3: M ANAGING YOUR S WITCH address and subnet mask that you want the switch to use when it is connected to the network. The final page displays a summary of the information entere d. 5 Select Save Configuration to save the con figuration to your switch. The initial setup of your switch is now complete and you can now set up your chosen m[...]

Setting Up Command Line Interface Management 47 The initial set up of your switch is now complete and you can set up your management method. See “Meth ods of Man aging a Switch ” on pa ge 36. Setting Up Command Line Interface Management This section describes how you can set up command line inte rface management using a local console port conne[...]

48 C HAPTER 3: M ANAGING YOUR S WITCH If the login pr ompt does not disp lay immedi ately , press Return a few times until it starts. 6 If you have logged on correctly , the switch you want to manage is displayed as <4210> , as shown in on page 44. Setting Up Command Line Interface Management using SSH T o set up command line interface manage[...]

Setting Up SNMP Management 49 Web Management Over the Network T o manage a switch using the web interface over an IP network: 1 Check that you have the IP protocol co rr ectly installed on your management workstation. Y ou can check this by trying to br owse the World Wide Web. If you can browse, the IP pr otocol is installed. 2 Check you can commu[...]

50 C HAPTER 3: M ANAGING YOUR S WITCH Default Users and Passwords If you intend to manage the switch using the web interface or the command line interface, or to change th e default passwor ds, you need to log in with a valid user name and password. The switch has thr e e default user names, and each user name has a differ ent password and level of[...]

4 P RO B L E M S OLVING This chapter helps you to diagnose and solve problems you may have with the operation of your switch. There is also an explanation of IP addr essing and upgrading software. The topics covered ar e: ■ Solving Problems Indicated by LEDs ■ Solving Har dware Problem s ■ Solving Communication Problems ■ Solving Fabric For[...]

52 C HAPTER 4: P ROBLEM S OLVING Solving Problems Indicated by LEDs If the LEDs on the switch indicate a problem, r efer to the list of suggested solutions below . The PWR LED does not light Check that the power cable is firmly conne cted to the switch and to the supply outlet. If the connection is secur e and there is still no power , you may have[...]

Solving Hardware Problems 53 So l v in g H ard w are Problems In the rare event of your switch unit expe riencing a hardwar e failur e, r efer to the list of suggested solutions below . A fan failur e warning message is r eceived Y our switch has a fan monitoring system that will generate fan failure warning messages. Fan fa ilur e could poten tial[...]

54 C HAPTER 4: P ROBLEM S OLVING Error message indicating that the SFP transceiver is invalid The switch has identified that the S FP does not meet the minimum requirements for the switch and has disabled the port. T o correct this problem, completely remove the SFP and r eplace it with a 3Com approved SFP . Error message indicating that the SFP tr[...]

Solving Fabric Formation Problems 55 another device on yo ur network. 3Com suggest s you use addresses in the range 192.168.0.0 to 192.168.255.255 wi th a subnet mask of 255.255.255.0. These suggested IP ad dresses are part of a group of IP addresses that have been set aside specially for use ‘in house’ only . Solving Fabric Formation Problems [...]

56 C HAPTER 4: P ROBLEM S OLVING[...]

A P IN - OUTS Null Modem Cable RJ-45 to RS-232 25 -pin PC-A T Serial Cable RJ-4 5 to 9-pin Screen TxD RxD Ground RTS CTS DSR DCD DTR Screen RxD TxD Ground RTS DTR CTS DSR DCD Shell 3 2 5 7 8 6 1 4 1 3 2 7 4 20 5 6 8 Switch 5500 Cable connector: RJ-45 female PC/T erminal Cable connector: 25-pin male/female only required if screen always required req[...]

58 C HAPTER A: P IN - OUTS Modem Cable RJ-45 to RS-232 25-pin Ethernet Port RJ-45 Pin Assignments 10/100 and 1000BASE-T RJ-4 5 connections. T able 10 Pin assignments T able 11 Pin assignments Screen TxD RxD RTS CTS DSR Ground DCD DTR Screen TxD RxD RTS CTS DSR Ground DCD DTR Shell 3 2 7 8 6 5 1 4 1 2 3 4 5 6 7 8 20 Switch 5500 Cable connector: RJ-4[...]

B O BTAINING S UPPORT FOR Y OUR 3C OM P RO D U C T S 3Com offers pr oduct re gistration, case management, and repair services through eSupport.3com.com . Y ou must have a use r name and passwor d to acce ss these services, which are described in this appendix. Register Y our Product to Gain Service Benefits T o take advantage of warra nty and other[...]

60 C HAPTER B: O BTAINING S UPPORT FO R Y OUR 3C OM P RODUCTS T o obtain software r eleases that follow the software version that you originally purchased, 3Com recommends that you buy an Express or Guardian contract, a Software Upgrades contract, or an equiva lent su pport contract from 3Com or your reseller . Support contracts that incl ude softw[...]

Contact Us 61 When you contact 3Com for assistance, please have the following information ready: ■ Product model name, part number , and serial number ■ A list of system har dware and softwar e, including r evision level ■ Diagnostic error messages ■ Details about recent configur ation changes, if applicable T o send a product dir ectly to [...]

62 C HAPTER B: O BTAINING S UPPORT FO R Y OUR 3C OM P RODUCTS Austria Belgium Denmark Finland France Germany Hungary Ireland Israel Italy 0800 297 468 0800 71429 800 17309 0800 113153 0800 917959 0800 182 1502 06800 12813 1 800 553 117 180 945 3794 800 879489 Luxembourg Netherlands Norway Poland Portugal South Africa Spain Sweden Switzerland U.K. 8[...]

C 3C OM N ETWORK M ANAGEMENT 3Com has a r ange o f network managemen t applications to address networks of all sizes and complexity , from sma ll and medium businesses thr ough large enterprises. The applications include: ■ 3Com Netw ork Super visor ■ 3Com Net work Dir ector ■ 3Com Netw ork Access M anager ■ 3Com Enterp rise Manag ement Sui[...]

64 A PPENDIX C: 3C OM N ETWORK M ANAGEMENT T o find out more about how 3Com Network Dir ector can help you manage your 3Com network and to download a trial version, go to: www .3 com.com/3nd 3Com Network Access Manager 3Com Network Access Manager is insta lled seamlessly into Microsoft Active Directory and Internet Authentication Service (IAS). It [...]

3Com Enterp rise Managem ent Suit e 65 3Com Enterprise Management Suite 3Com Enterp rise Manag ement Suite (EMS ) delivers comprehensive management that is flexible and scalable enough to meet the needs of the largest enterpr ises and advanced netwo rks. This solution pr ovides particularly powe rful configuration and change control functionalities[...]

66 A PPENDIX C: 3C OM N ETWORK M ANAGEMENT[...]

D R EDUNDANT P OWER S UPPLY S AFETY I NFORMATION Important Safety Information WAR NI N G: Th is device has more than on e power inpu t. Disconnect all power inputs to power off this device. WAR NI N G: Th e installation of the Red undant Power Su pply (RPS) should only be carried out by properly trained and qualified personnel. WAR NI N G: These in[...]

68 A PPENDIX D: R EDUNDANT P OWER S UPPLY S AFETY I NFORMATION L ’information de Sé curité Importante A VERTISSEMENT : Ce périphérique comport e plus ieurs entrées d'alimentation. Déconnectez tout es les entrées d'alimentation afin de le mettre hors tension. A VERTISSEMENT : L'installation du RPS (Redundant Power Supply) ne [...]

Información de Seguridad Importante 69 VORSICHT : Diese Anleitungen müssen im Zusammenhang mit den Sicherheitshinweisen und Installatio nsanl eitungen zu Ihrer RPS gelesen werden. VORSICHT : Bei der Stromversorgung eines Sw itch 4210 über eine RPS muss das Gerät geerdet sein. Hierfür kann entw eder das Netzkabe l an das Gerät angeschlossen we[...]

70 A PPENDIX D: R EDUNDANT P OWER S UPPLY S AFETY I NFORMATION conectando ambas. Deberá asegurarse de qu e la conexión a tierra se realiza ant es de conectar el suministro de CC del RPS. ADVERTENCIA: T odos los RPS deben estar homologados como salidas SEL V sin toma de tierra según IEC 60950-1/UL 60950-1/EN 609 50-1. ADVERTENCIA: Estas instrucci[...]

Importanti Informazioni di Sicurezza 71 Importanti Informazioni di Sicurezza AVVERTENZA: Il dispositivo presenta più punti di alimentazione. Per spegne re il dispositivo, scollegare tutt i i punti di alimentazione. AV V E R T E N Z A : le op erazioni di installazione dell'RPS (Redundant Power Supply) devono essere eseguite esclusivam ente da [...]

72 A PPENDIX D: R EDUNDANT P OWER S UPPLY S AFETY I NFORMATION OSTRZE Ż ENIE: Instalacja zasilacza nadmiarowego (RPS) powinna by ć wykony- wana przez odpowiednio przeszkolony i wykwa lifikowany personel. OSTRZE Ż ENIE: T e instrukcje nale ż y przeczyta ć razem z instrukcjami doty- cz ą cymi bezpiecze ń stwa i instalacji dostarczo nymi z syst[...]

Regulatory Notices 73 Regulatory Notices FCC Statement This equipment has been tested and fo und to comply with the limits for a Class A digital device, pursuant to part 15 of the FCC rules. These limits are designed to provide reasonable protection against harmful interfe rence when the equipment is operated in a commercial environment. This equip[...]

74 A PPENDIX D: R EDUNDANT P OWER S UPPLY S AFETY I NFORMATION[...]