Wood and Douglas 1300 manuale d’uso

HERMES RADIO MODEM OPERATING INSTRUCTIONS (1892 1300) SPECIALIST RF DESIGNS © Copyright Wood & Douglas 2002 Version: 1.3 Issue: July 2002 LATTICE HOUSE BAUGHURST BASINGSTOKE UK RG26 5LP Tel: +44 (0) 118 981 1444 Fax: +44 (0) 118 981 1567[...]

Table Of Contents 1 INTRODUCTION .............................................. 4 2 CONNECTIONS & INDICATIONS ................................. 5 2.1 RS232 Connector ....................................... 5 2.2 Power Connector ........................................ 6 2.3 RF Connector ........................................... 6 2.4 Front Pa[...]

Hermes Operator Note Page 3 of 32 5 HARDWARE SPECIFICATION .................................. 28 5.1 Introduction ........................................... 28 5.2 RS232 Port Parameters .................................. 28 5.3 Radio Specifications .................................... 29 6 MECHANICAL SPECIFICATION ................................ [...]

Hermes Operator Note Page 4 of 32 1 INTRODUCTION This document describes the operation of the Wood and Douglas Hermes Radio Modem. The Hermes modems provide a transparent data link for a wide range of applications. The internal modem can be used with a range of Wood & Douglas RF products to give great choice in the operating frequency and trans[...]

Hermes Operator Note Page 5 of 32 2 CONNECTIONS & INDICATIONS 2.1 RS232 Connector The RS232 connections are made via a 9 way D female with the following connections: Pin No. Function 1 CD Output Set (+ve) when a RF signal above a certain level is present at the RF connector. The threshold is programmable over 10 levels that are defined in secti[...]

Hermes Operator Note Page 6 of 32 2.2 Power Connector The power and ancillary connections are made via a 9 way D male connector. The power supply input is fully isolated from the chassis of the module. Note: The power supply cannot be used as an RS232 input line. Pin No. Function 1 RSSI Received Signal Strength Output Analogue output proportional t[...]

Hermes Operator Note Page 7 of 32 3 MODEM OPERATION 3.1 Introduction The internal modem power supply system is turned on/off with the DTR input. The modem is ready after an initialisation period. The modem enters receive mode using the last set of configuration parameters (RF channel, squelch level etc). The modem starts the transmit sequence after[...]

Hermes Operator Note Page 8 of 32 3.3 Data Transfer Modes In FEC mode every byte of the data, including the "end-of-file" string is scrambled within the modem to ensure that the error correction mechanism operates over non-consecutive bits in the data stream. The frame sync pattern is not scrambled. In non-FEC (High Speed) mode the data i[...]

Hermes Operator Note Page 9 of 32 Figure 1 Timing Information Function Description Time (ms) G-MAX (9600 baud) SXn50 (19200 baud) t1 DTR input-to-modem DSR output <90 <90 t2 RTS input to CTS output <0.5 <0.5 t3 CTS output to Data input >0.1 >0.1 t4 Data input to RF output (non-FEC mode) <25 <25 Data input to RF output (FEC m[...]

Hermes Operator Note Page 10 of 32 4 LIST OF COMMANDS: 4.1 Command Mode The modem is configurable through the RS232 port. The Command Mode has to be activated to do this, as detailed in the following paragraphs: 4.1.1 Activation of the Command Mode: The Command Mode is activated with the string: <wait>+++<wait> <CR><LF> Wher[...]

Hermes Operator Note Page 11 of 32 4.1.2 Ending of Command Mode The command mode is ended by inputting the string: ATO<CR><LF> The modem responds with: OK<CR><LF> The modem is now ready for normal modem operation. Note that the communication parameters (baudrate etc) are the programmed parameters. 4.2 Command Syntax 4.2.1 No[...]

Hermes Operator Note Page 12 of 32 4.3 Baud Rate (AT B0) When the baud rate is changed, the change is made after the Command Mode is ended (with the AT O command). The baud rate is set with the following command: Baud Rate AT B0=n <CR><LF> Where: n = 1 4800 n = 2 9600 n = 3 19200 n = 4 38400 Default: n = 3 for 12.5kHz radios n = 4 for 2[...]

Hermes Operator Note Page 13 of 32 4.5 Format Mode (AT F) This command turns the Forward Error Correction (FEC) mode on and off. The over-air format allows for higher speed operation, but with reduced Bit Error Rate (BER) performance with the FEC turned off, or lower speed, improved BER with the FEC turned on. Figure 1 and the associated table give[...]

Hermes Operator Note Page 14 of 32 4.6 Engineering Test Modes (AT In) Format modes: To enable the function AT In=1 <CR><LF> To disable the function AT In=0 <CR><LF> Modem responds with OK <CR><LF> Read status: AT In?<CR><LF> Modem responds with m <CR><LF> where m=0, not active m=1, active [...]

Hermes Operator Note Page 15 of 32 4.7 Software Version Information (AT I9) This command tells the modem to output information about the software version. Example: ATI9=1<CR><LF> return software version or ATI9<CR><LF> Return: ‘an ASCII string detailing the ID and versions of the internal processors’ <CR><LF>[...]

Hermes Operator Note Page 16 of 32 The centre radio frequency of the modem is set as follows: AT S155=nnn.nnnnnn<CR><LF> Where: nnn.nnnnnn is the format of the input string for the frequency in MHz Default: current centre frequency. Read: AT S155?<CR><LF> Read Return: nnn.nnnnnn<CR><LF> Example: AT S155=458.5<[...]

Hermes Operator Note Page 17 of 32 The RSSI level is requested with the command: AT S156?<CR><LF> Read Return: nn<CR><LF> The data can be added to the end of each received packet as defined in paragraph 5.6. 4.11 Radio Channel (AT S157) The radio transceiver is programmed with a centre frequency (using the AT S155 command). [...]

Hermes Operator Note Page 18 of 32 4.13 Squelch (AT S159) This command sets the squelch threshold to one of 10 pre-set levels as shown in the Table 6. This command enables the user to reduce the chances of local interference showing the channel to be busy which could reduce the occupancy of the system. Squelch Level Level at RF Input ( dBm ±2dB) 1[...]

Hermes Operator Note Page 19 of 32 4.14 Transmission Power (AT S160) The command enables the RF transmit power to be modified. Different RF units have different capabilities and may change, depending on what is supplied. The SXn50 range of transceivers have 2 levels only. The levels for the 1W and 2W versions of the G-MAX are shown in Table 7. Tabl[...]

Hermes Operator Note Page 20 of 32 The power is set with the command: AT S160=n<CR><LF> Where: sets the power threshold <1 to 10> Default: 10 Read AT S160?<CR><LF> Read Return: nn<CR><LF> Example: AT S160=-10<CR><LF> sets the power level to 10 4.15 Channel Step Size (AT S161) This command sets t[...]

Hermes Operator Note Page 21 of 32 4.17 Over-Air Symbol Rate (AT S163) Note: engineering function only. This command sets the over-air baud rate to enable the modem to be used with different radios and channel spacings. The command format is: AT S163=n<CR><LF> Where: n = 2 4800 symbols/sec n = 3 9600 symbols/sec Default: n = 2 4800 for [...]

Hermes Operator Note Page 22 of 32 4.19 Frame Synch Tolerance (AT S166) Note: engineering function only. This command controls a receive function within the FX929 modem IC within the modem.. The command format is as follows: AT S166=n<CR><LF> Where: n = 0 0 mismatches allowed in frame synch. pattern n = 1 2 mismatches allowed in frame s[...]

Hermes Operator Note Page 23 of 32 4.21 Squelch Delay (AT S168) Note: engineering function only. This command changes the delay between the Squelch being received and the FX929 modem IC looking for preamble in the receive audio. This allows the modem to be used with different transceivers. The command format is as follows: AT S168=n<CR><LF[...]

Hermes Operator Note Page 24 of 32 4.24 Radio Frequency (AT &F) The Hermes is programmed with a factory set centre frequency that is the centre of the RF switching band. A new frequency can be entered directly within the ±99 channels of the centre frequency using this command. The channel number is re-calculated for the frequency entered using[...]

Hermes Operator Note Page 25 of 32 4.27 Display parameters (ATT?) Displays all the AT settings. The command for this is: ATT?<CR><LF> The modem responds with: 2, 3, 0, 010, 429.850000, XX, +00, XXX, 02, 05, 2, 020, 2, 08, 0, 0, 050, 1, 429.850000 <CR><LF> The order of the data is: 2 baud rate 3 parity 0 format mode 010 comma[...]

Hermes Operator Note Page 26 of 32 4.28 Code Loader (AT S2000) Warning once activated, a code load must be carried out DO NOT enter unless you wish to carry out a code load This command enables the firmware contained within the modem to be upgraded using a simple terminal program. The baud rate for the link is fixed at 19,200 baud with no parity. T[...]

Hermes Operator Note Page 27 of 32 A typical programming sequence display is as follows: PPPPP........................................................................... ................................................................................ ................................................................................ ..................[...]

Hermes Operator Note Page 28 of 32 5 HARDWARE SPECIFICATION 5.1 Introduction The hardware of the modem part of the system is based on the FX929B modem chip from Consumer Microcircuits Ltd (CML). The radio part of the system can be either the G-MAX "rugged" transceiver, or the lower power SXn50 range of transceivers. The interface between [...]

Hermes Operator Note Page 29 of 32 5.3 Radio Specifications The transceiver specifications are detailed in the appropriate handbook for the SXn50 family and the G-Max. Throughout the handbook, the differences between the two types of transceiver have been highlighted. A brief summary of the maion characteristics are listed below: Parameter G-Max SX[...]

6 MECHANICAL SPECIFICATION 6.1 Enclosures 6.1.1 Casting Enclosure The casting enclosure is shown in Figure 2. The enclosure has 4 off M4 fixings. There are raised bosses on the base of the unit to enable water to run underneath the unit when mounted on a vertical surface. Figure 3 shows the connector layout under the protective casting overhang whi[...]

Hermes Operator Note Page 31 of 32 Figure 2 Front View of Casting Figure 3 Rear View of Casting Figure 4 3U Enclosure[...]

Wood & Douglas Ltd Lattice House, Baughurst Road, Tadley Hants RG26 5LP 1892 1300 Tel: +44(0) 118981 1444. Fax: +44(0) 118981 1567 1.3/July 2002 6.2 Operating conditions Operating temperature: -25 - + 55° C Storage temperature: - 30 - + 70° C Relative humidity: 20- 80% non-condensing 6.3 Vibration Specifications: When the G-MAX transceiver is[...]