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Tait T2000-A76 Operation Manual

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T2000-A76 AVL Modem
Operation Manual
March 2003
© Tait Electronics Limited
Corporate HQ: PO Box 1645, Christchurch,
New Zealand.
Tel: +64 3 358 3399
Fax: +64 3 358 0340
Web: www.taitworld.com/
M2303-00-P00-805

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  • Page 1 T2000-A76 AVL Modem Operation Manual March 2003 © Tait Electronics Limited Corporate HQ: PO Box 1645, Christchurch, New Zealand. Tel: +64 3 358 3399 Fax: +64 3 358 0340 Web: www.taitworld.com/ M2303-00-P00-805...

  • Page 3: Table Of Contents

    Contents Section Title Page Overview Operation Compatibility GPS Interfaces Programming the A76 Operation Sequences Commands to the Remote Radio Responses from the Remote Radio CCDI Reference...

  • Page 5: Overview

    Overview The T2000-A76 AVL Modem is fitted as an options PCB within a T201X mobile radio. The AVL enabled T201X radio collects and stores AVL data from a GPS receiver in its internal memory, which can then be relayed to central control equipment.

  • Page 6: Operation

    ‘0’. Radio Signalling The signalling between the despatcher radio and the remote AVL radio uses the Tait CCDI V2.0 terminal and over-air protocol. CCDI Short Data Messages (SDMs) are used to send commands to the remote AVL radio and to pass information back to the central control computer.
  • Page 7 A76 database must be done using NMEA sentences rather than sending a standard CCDI Program command as is used with both the T2000-A75 Modem and the Tat Orca/Tait Radio Modem. For this purpose four new Tait proprietry NMEA messages have been created: •...

  • Page 8: Compatibility

    The Lead In Delay can be reprogrammed as low as 40 ms, but the Economy mode must be disabled. Despatcher Radio PGM Settings The despatcher radio may be a Tait Orca, a Tait Radio Modem or a T2000 with a A75 fitted. Regardless of which radio is used, the modem must have Auto Acknowledge set to disabled.

  • Page 9: Gps Interfaces

    T2002-A00 supply T2003-A00 supply Not used * not available in the standard T201X without a T2000-A76 PCB fitted. Caution: Note that RS232 pin labelling can be misleading. A straight-trough cable is used to connect the GPS receiver to the T201x radio..
  • Page 10 RS232 from Remote Radio to GPS Receiver The NMEA data transfer between the Remote AVL radio and the GPS receiver uses only the RXD data line. CTS and RTS are used to active/deactivate the Aux Control line and Emergency mode respectively. NMEA-0183 RMC Sentence Format The NMEA RMC sentence is sent by the GPS receiver to the A76 in the remote AVL radio.
  • Page 11 sentence part information type Definition latitude reference N = north S = south 12345.123 longitude 123 degrees : three fixed digits 45.123 minutes : two fixed digits plus up to three optional decimal points longitude reference E = east W = west speed over ground variable length field with up to three digits (knots)

  • Page 12: Programming The A76

    Before the A76 can operate, the radio must be configured correctly. The PROGRAM command is used to set up the default configuration of the A76. An Tait PC application is available for this. As the serial port of the A76 is expecting NMEA data, the programming command must be in NMEA type format.
  • Page 13 [ITEM2] AVL Report Delay Time : default = 10h (1600ms) Two ASCII hex characters. The time that the A76 delays after receiving an Poll command until it sends back the response SDM. Range : 01 to FFh (25600) in steps of 100 ms. Refer to the section. [ITEM3] SDM Lead In Delay : default = 10h (320ms Two ASCII hex characters.

  • Page 14: Operation Sequences

    Operation Sequences Polling the Remote AVL radio A simple AVL Poll is sent from the PC AVL application to the remote AVL radio. The remote radio automatically responds with an AVL report. The AVL Poll command is sent by the despatcher radio using a SEND_SDM command. The SDM contains instructions about sending the AVL report to either the default address (defined in the A76 configuration) or to a specified address sent with the command.
  • Page 15 Auxiliary Output Control The auxiliary output from the A76 uses the RS232 CTS line on the A76 serial port to switch external devices on or off. It can be remotely controlled by the despatcher radio by sending a AUX ON or AUX OFF message. This feature can be enabled or disabled by the A76 configuration.
  • Page 16 Emergency Mode Activation An emergency switch can be connected to the RS232 RTS input on the A76 serial port. When the switch is activated, the AVL radio sends an Emergency AVL report to the despatcher radio. The operation of Emergency mode is controlled by the following configuration items - refer to the Configuration section: •...

  • Page 17: Commands To The Remote Radio

    Commands to the Remote Radio Commands to the remote radio are sent using the SEND_SDM CCDI command. It has the format : s [LEAD_IN_DELAY] [DATA_MESSAGE_ID] [COMMAND] [DATA] Notes: The [DATA] field is only sent with some commands. The [COMMAND] and [DATA] fields are limited to a combined length of 32 hex characters. The SEND_SDM is sent by the central control AVL application to the despatcher radio, then, after the specified SDM Lead In Delay, over-air to the remote AVL radio.
  • Page 18 [MESSAGE] Function first byte Bit 0 - 2 Parameter The Parameter is set depending on the Command Type that is sent. Refer to the table below for the Parameter options. Bit 3 Return Address 0 : the AVL report is sent to the default despatcher address 1 : the AVL report is sent to the return address specified.
  • Page 19 Command Type C Parameters A76 Action / Response Bits 4,5 and 6 Bits 0,1 and 2 Poll 000 : poll the AVL report. Always set to 000. AVL report is sent 001 - 111 : the command will be ignored If a return address is sent, it is sent in the [DATA] bytes.
  • Page 20 Command Type Parameters A76 Action / Response Bits 4,5 and 6 Bits 0,1 and 2 Control AUX 000 : sets the AUX (CTS) signal to ON A ‘Control AUX ACK’ is sent 001 : sets the AUX (CTS) signal to OFF back 010 - 111 : the command will be ignored If a return address is sent, it is sent in the [DATA]...

  • Page 21: Responses From The Remote Radio

    Responses from the Remote Radio Commands sent to the remote AVL radio generally require a response. The Reset command is the only exception to this. The response from the remote radio is sent as an SDM. It has the format : [RESPONSE] [DATA] The SDM is sent by the remote AVL radio over-air to the despatcher radio where it is then retrieved by the AVL application using the GET_SDM CCDI command.
  • Page 22 Response Type Radio Status / ACK Parameters Bits 4,5 and 6 Bits 0,1,2 and 3 AVL Report Bits 0 and 1 are used to send error handling information, where 00 : AVL report sent with new data OK 01 : AVL report sent with old data 10 : GPS receiver down, no data sent, no AVL report to be sent 11 : Data format error, no AVL report to be sent Bit 2 is used it send Emergency mode status, where...
  • Page 23 [DATA] The [DATA] field contains either an AVL Report or other data dependent on the type of acknowledgement being sent. Refer to the previous table for acknowledgement details. AVL Report Note: If no AVL data is received within 20 seconds or a format error occurs in the RMC data (incorrect check- sum), then the AVL report is not send.

  • Page 24: Ccdi Reference

    CCDI protocol, the despatched radio must have a CCDI interface (e.g. Tait Orca, Tait Radio Modem or T201x with an A75 fitted). The over-air CCDI protocol is not described as the CCDI interface at the despatcher radio described in this manual is the only way to communicate with the A76 radio.
  • Page 25 Checksum Example s0D050800TESTHi!DA 1. Take the modulo-2 sum of all message bytes preceding [CHECKSUM]. • s = 73h, 0 = 30h, D = 44h etc. therefore the modulo-2 sum is: 73 + 30 + 44 + 30 + 35 + 30 + 38 + 30 + 30 + 54 + 45 + 53 + 54 + 48 + 69 + 21 = 426h 2.
  • Page 26 GET_SDM (despatcher radio to PC) Solicited. The GET_SDM message is sent to the PC in response to a QUERY command. The modem sends the SDM text message which is saved in the EEPROM. It has the format : s [SDM_DATA] PARAMETER Function [SDM_DATA]...
  • Page 27 PROGRESS (despatcher radio to PC) Unsolicited. The PROGRESS message advises the PC of modem status when some significant change of state in the radio occurs (typically during call processing). It has the format : p [PTYPE] [PARA1] [PARAMETER] Function [PTYPE] A two-digit string representing a decimal number in the range of 00 to 99 which can identify the progress message category.
  • Page 28 Example An example of an ‘Progress’ message is: p0207C7 Message Field Parameter Response [IDENT] PROGRESS. [SIZE] Size of parameter field [PARAMETERS] [PTYPE] = 07; the PTT mic has been activated by the FUNCTION command [CHECKSUM] The checksum for the message string, calculated by the modem M2303-00-P00-805 March 2003...
  • Page 29 QUERY (PC to despatcher radio) The QUERY command requests the modem to respond with data. The data can contain several types of information. It has the format : q [QUERY_TYPE] [PARAMETER] Function [QUERY_TYPE] A single ASCII hex character representing the query type. [QUERY_TYPE] = 0 Query Model message.
  • Page 30 SEND_SDM (PC to despatcher radio) The SEND_SDM command requests the modem to send a Short Data Message (SDM). The PC sends the SDM directly to the A76, and the T201X immediately keys up the transmitter. After the specified SDM Lead In Delay the modem sends the SDM.

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