Page 3 - Hermes Operator Note Page 3 of 32
Hermes Operator Note Page 3 of 32 5 HARDWARE SPECIFICATION . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 5.1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 28 5.2 RS232 Port Parameters . . . . . . . . . . . . . . . . . . . ...
Page 4 - Hermes Operator Note Page 4 of 32; INTRODUCTION
Hermes Operator Note Page 4 of 32 1 INTRODUCTION This document describes the operation of the Wood and Douglas HermesRadio Modem. The Hermes modems provide a transparent data link for a wide range ofapplications. The internal modem can be used with a range of Wood &Douglas RF products to give gr...
Page 5 - Hermes Operator Note Page 5 of 32; CONNECTIONS & INDICATIONS
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 followingconnections: Pin No. Function 1 CD OutputSet (+ve) when a RF signal above a certain level is present at theRF connector. The threshold is progra...
Page 6 - Hermes Operator Note Page 6 of 32; Power Connector
Hermes Operator Note Page 6 of 32 2.2 Power Connector The power and ancillary connections are made via a 9 way D maleconnector. The power supply input is fully isolated from the chassis of themodule. Note: The power supply cannot be used as an RS232 input line. Pin No. Function 1 RSSI Received Signa...
Page 7 - Hermes Operator Note Page 7 of 32; MODEM OPERATION; Handshaking is also required during the code loading.
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 DTRinput. The modem is ready after an initialisation period. The modem entersreceive mode using the last set of configuration parameters (RF channel,squelch level etc...
Page 8 - Hermes Operator Note Page 8 of 32; Data Transfer Modes
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 mechanismoperates over non-consecutive bits in the data stream. The frame syncpattern is not scra...
Page 9 - Hermes Operator Note Page 9 of 32; Figure 1; Timing Information; Function; RTS input to CTS output
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 ...
Page 10 - Hermes Operator Note Page 10 of 32; Command Mode; The Command Mode is activated with the string:
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 Modehas 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: <...
Page 11 - Hermes Operator Note Page 11 of 32; Command Syntax
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 ...
Page 12 - Hermes Operator Note Page 12 of 32
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 CommandMode 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 38...
Page 13 - Hermes Operator Note Page 13 of 32; Format mode
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 BitError Rate (BER) performance with the FEC turned off, or lower speed,improved BER with the FEC t...
Page 14 - Hermes Operator Note Page 14 of 32
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 <C...
Page 15 - Hermes Operator Note Page 15 of 32; return software version
Hermes Operator Note Page 15 of 32 4.7 Software Version Information (AT I9) This command tells the modem to output information about the softwareversion. Example: ATI9=1<CR><LF> return software version or ATI9<CR><LF> Return: ‘an ASCII string detailing the ID and versions of ...
Page 16 - Hermes Operator Note Page 16 of 32; The centre radio frequency of the modem is set as follows:; RSSI Level; XX
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 thefrequency in MHz Default: current centre frequency. Read: AT S155?<CR><LF> Read Return: nnn.nnnn...
Page 17 - Hermes Operator Note Page 17 of 32; The RSSI level is requested with the command:
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 inparagraph 5.6. 4.11 Radio Channel (AT S157) The radio transceiver is programmed with...
Page 18 - Hermes Operator Note Page 18 of 32; Squelch Level; Table 6 Squelch Levels
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 asshown in the Table 6. This command enables the user to reduce the chances of local interferenceshowing the channel to be busy which could reduce the occupancy of thesystem....
Page 19 - Hermes Operator Note Page 19 of 32; Table 7 Power Levels for G-MAX Radios
Hermes Operator Note Page 19 of 32 4.14 Transmission Power (AT S160) The command enables the RF transmit power to be modified. Different RFunits have different capabilities and may change, depending on what issupplied. The SXn50 range of transceivers have 2 levels only. The levels for the 1Wand 2W v...
Page 20 - Hermes Operator Note Page 20 of 32; The power is set with the command:
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 4.1...
Page 21 - Hermes Operator Note Page 21 of 32; for 25kHz radios
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 usedwith different radios and channel spacings. The command format is: AT S163=n<CR><LF> Where: n = 2 4800 symbols/se...
Page 22 - Hermes Operator Note Page 22 of 32
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 withinthe modem.. The command format is as follows: AT S166=n<CR><LF> Where: n = 0 0 mismatches allowed in frame syn...
Page 23 - Hermes Operator Note Page 23 of 32; Read
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 andthe FX929 modem IC looking for preamble in the receive audio. This allowsthe modem to be used with different transceivers. The command...
Page 24 - Hermes Operator Note Page 24 of 32; The radio frequency of the modem is set as follows:
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 thecentre of the RF switching band. A new frequency can be entered directlywithin the ±99 channels of the centre frequency using this command. The channel number i...
Page 25 - Hermes Operator Note Page 25 of 32
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...
Page 26 - Hermes Operator Note Page 26 of 32; Warning
Hermes Operator Note Page 26 of 32 4.28 Code Loader (AT S2000) Warning once activated, a code load must be carried outDO NOT enter unless you wish to carry out a code load This command enables the firmware contained within the modem to beupgraded using a simple terminal program. The baud rate for th...
Page 27 - Hermes Operator Note Page 27 of 32; A typical programming sequence display is as follows:
Hermes Operator Note Page 27 of 32 A typical programming sequence display is as follows: PPPPP.................................................................................................................................................................................................................
Page 28 - Hermes Operator Note Page 28 of 32; HARDWARE SPECIFICATION; Baud rates
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 FX929Bmodem chip from Consumer Microcircuits Ltd (CML). The radio part of thesystem can be either the G-MAX "rugged" transceiver, or the lower powerSXn50 ...
Page 29 - Hermes Operator Note Page 29 of 32; Radio Specifications; A brief summary of the maion characteristics are listed below:; Parameter; TX Power
Hermes Operator Note Page 29 of 32 5.3 Radio Specifications The transceiver specifications are detailed in the appropriate handbook forthe SXn50 family and the G-Max. Throughout the handbook, the differencesbetween the two types of transceiver have been highlighted. A brief summary of the maion char...
Page 30 - Hermes Operator Note Page 30 of 32
6 MECHANICAL SPECIFICATION 6.1 Enclosures 6.1.1 Casting Enclosure The casting enclosure is shown in Figure 2. The enclosure has 4 off M4fixings. There are raised bosses on the base of the unit to enable water torun underneath the unit when mounted on a vertical surface. Figure 3 shows the connector ...
Page 31 - Hermes Operator Note Page 31 of 32; Figure 2; Front View of Casting; Figure 3; Rear View of Casting; Figure 4; U Enclosure
Hermes Operator Note Page 31 of 32 Figure 2 Front View of Casting Figure 3 Rear View of Casting Figure 4 3U Enclosure
Page 32 - Operating conditions; Operating temperature:; Vibration Specifications:; Hermes Operator Note Page 32 of 32
Wood & Douglas LtdLattice 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 Vibratio...
