Related Manuals for Tait T2000-A75
Summary of Contents for Tait T2000-A75
- Page 1 T2000-A75 Modem Operation Manual November 2001 © Tait Electronics Limited Corporate HQ: PO Box 1645, Christchurch, New Zealand. Tel: +64 3 358 3399 Fax: +64 3 358 0340 M2256-000-00-051 Web: www.taitworld.com/...
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Page 3: Table Of Contents
Contents Section Title Page Overview RS232 Interface Compatibility A75 Configuration Command mode Transparent mode Changing Modes Transparent Mode Operation Transparent Mode effective data rate calculation Transparent Mode RTS/CTS Signalling Command Mode Operation Message Format Calculating the [CHECKSUM] Sending and Receiving Short Data Messages (SDM) Commands... -
Page 5: Overview
PC and the A75. The over-air data rate is either 1200 or 2400 baud. The T2000-A75 modem described in this manual is CCDI version 2.0 compatible. When an A75 is retrofitted to a T2000 radio, some hardware modifications are needed. Refer to the A75 fitting instructions for details. -
Page 6: Rs232 Interface
RS232 Interface The RS232 communication between the PC and the A75 has the following parameters which are fixed in the A75 firmware. For every byte sent, there are 10 bits sent including the start and stop bits: • Number of data bits = 8 •... -
Page 7: A75 Configuration
A75 Configuration The A75 is configured for both Command and Transparent mode communication using the PROGRAM command. It contains 18 ASCII hex characters and sets up the following parame- ters: • Transparent mode baud to either 1200, 2400, 4800 or 9600 baud •... -
Page 8: Command Mode
Command mode In Command mode, the PC sends command sequences to the A75 and waits for a prompt before beginning the next transaction. The A75 sends a prompt character ‘.’ to the PC to indicate that it is ready to accept a new command. Some commands require the A75 to send a CCDI message in response, before it sends the prompt. -
Page 9: Changing Modes
If the T201X defaults to Transparent mode at power-up, the escape character is set to the default value of ‘+’. Example A70(2) PC(1) A70(1) PC(2) or Tait Orca [SIZE] [CHECKSUM] ‘.’ Transparent mode (2s idle) + zzz + (2s idle) ‘.’... - Page 10 M2256-000-00-051 November 2001...
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Page 11: Transparent Mode Operation
Transparent Mode Operation The Transparent Mode transmission format is as follows: Lead In First block ..nth block Tail Time Delay (maximum 46 (maximum 46 ( 20ms) (200ms) bytes) bytes) Preamble Sync Length data block dummy CRC (maximum... - Page 12 Transparent mode Lead In Delay Lead In Delay time ensures that data is not lost from the front of the data block while the transmitter keys-up. To achieve this, inhibit is set to ‘0’ so that radio does not receive any serial data from the PC during the Lead In Delay.
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Page 13: Transparent Mode Rts/Cts Signalling
RTS and CTS signals as determined by data rate considerations. Transparent Mode data rate considerations The A75 has a 50 byte Serial Input buffer and 54 byte Serial Output buffer. or Tait Orca Terminal • The PC baud is set up in the terminal program. - Page 14 RTS (Request to Send) Signal RTS is an active high input signal to theA75 from the PC and is used to reduce data transfer delays and improve data throughput. RTS Inhibit is either inhibited or not, using bit 6 of the [ITEM1] parameter in the PROGRAM command which configures the A75.
- Page 15 If the data stream has a gap, while RTS remains on, the A75 continues to transmit. This elimi- nates the data delay caused by the Lead In Delay at the start of each transmission. RTS on buffer RTS Inhibit=0 Time empty data A75 PTT Tx...
- Page 16 CTS (Clear to Send) Handshaking CTS is an active high output signal from the A75 to the PC and is used to prevent data over- flow under certain conditions such as a full input buffer. CTS should always be used if the PC and A75 baud is higher than the over-air baud.
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Page 17: Command Mode Operation
Command Mode Operation Message Format All Command mode message packets take the general form: [IDENT] [SIZE] [PARAMETERS] [CHECKSUM] <CR> Field Description [IDENT] The message identifier. Identifiers are single ASCII characters (lower-case alphabetical) which categorise the message type. [SIZE] The number of characters which make up the [PARAMETERS] field. [SIZE] is an 8-bit number expressed in ASCII-hex notation (two characters). -
Page 18: Calculating The [Checksum]
Calculating the [CHECKSUM] [CHECKSUM] is calculated by applying the following algorithm: 1. Take the modulo-2 sum of all message bytes preceding [CHECKSUM]. 2. Retain bits 0 to 7, discarding any higher order bits resulting from the summation. 3. Form the two’s complement of the remainder. 4. -
Page 19: Sending And Receiving Short Data Messages (Sdm)
A75 with the PROGRAM command or in the PGM programming software for the Tait Orca. If the A75 has SDM Auto ACK is set to ‘1’ (enabled) in bit 7 of the [ITEM1] parameter of the PROGRAM command, then: •... - Page 20 Auto ACK = 0 or 1 Auto ACK = 1 A75(2) A75(1) PC(1) PC(2) or Tait Orca FF12345678Hi [SIZE] [CHECKSUM] SEND_SDM Lead In Delay PROGRESS Delay Time PROGRESS [SIZE] [CHECKSUM] ACK triggers PROGRESS RS232 over air RS232 In the example above, the receiving modem A75(2) has the...
- Page 21 Receiving SDMs When the A75 receives an SDM, it sends a PROGRESS message of [PTYPE] SMD Data Re- ceived (1E) with the flag set to ‘1’ or ‘0’ depending on whether the SDM contained a [MES- SAGE] parameter. Refer to the PROGRESS command details for further information.
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Page 23: Commands
Commands In all cases, if a command is received without error at the A75 and all parameters are valid, the command is executed. The prompt character ‘.’ is then returned to the PC after the A75 com- pletes the current transaction, to signify that another may begin. If an error arises, the PC is no- tified with an appropriate ERROR response. - Page 24 CANCEL (PC to A75) The CANCEL command allows the PC to clear the currently received SDM data. [IDENT] [CANCEL_TYPE] [PARAMETERS] [PARAMETER] Function [CANCEL_TYPE] A single ASCII hex character representing the cancelling type. Delete SDM data [CANCEL_TYPE] = 1 . This will delete last received SDM text data in the A75 EEPROM. If there is no valid SDM data, it will do nothing.
- Page 25 ERROR (A75 to PC) Solicited and Unsolicited. A Transaction ERROR message is solicited and advises the PC that the A75 has detected an er- ror condition and cannot proceed with the current transaction. A System error is unsolicited and occurs where an exceptional condition occurs in the A75 independent of any control transac- tions.
- Page 26 Note: During the initialisation, if the database for A75 is invalid, then the database is initialised with ‘#12C401060A010000BASE8F’ as the configuration and the Transaction error ‘CCDI Parameter Error’ is generated. Example An example of an ‘Error’ message is: e03002A6 Message Field Parameter Response [IDENT]...
- Page 27 FUNCTION (PC to A75) The FUNCTION command provides access to some miscellaneous functions. [IDENT] [FUNCTION] [QUALIFIER] [PARAMETERS] [PARAMETER] Function [FUNCTION] A single ASCII hex character representing the required function category. [QUALIFIER] A single ASCII hex character representing the action to be taken. The meaning of [QUALIFIER] is dependent upon the value of [FUNCTION].
- Page 28 GET_SDM (A75 to PC) Solicited. The GET_SDM message is sent to the PC in response to a QUERY command. The A75 sends the SDM text message which is saved in the EEPROM. [IDENT] [SDM_DATA] [PARAMETERS] [PARAMETER] Function [SDM_DATA] This can be a maximum of 32 characters. If there is any buffered SDM data in the EEPROM, the SDM data is sent to the PC.
- Page 29 GO_TO_CHANNEL (PC to A75) The GO_TO_CHANNEL command forces the A75 to send a new channel number to its BCD output. This will cause a channel change on the T201X radio [IDENT] [CHANNEL_NO] [PARAMETERS] [PARAMETER] Function [CHANNEL_NO] Channel number . A string of characters representing the new channel number. The range of allowed characters is 0 to.9, and the maximum number of digits is 3.
- Page 30 MODEL (A75 to PC) Solicited. The MODEL message is sent to the PC in response to a QUERY command. It identifies the type of T201X radio and the version of CCDI software operating in the T201X radio. [IDENT] [RU_TYPE] [RU_MODEL] [RU_TIER] [VERSION] [PARAMETERS] [PARAMETER] Function...
- Page 31 1 : Power-up Default is Transparent Mode Bit3 Over-Air Baud 0 : 1200 bps 1 : 2400 bps (Note: the Tait Orca does not support 2400 baud) Bit4 Command Mode Baud 0 : 9600 bps fixed 1 : The same bps as Transparent Mode Baud...
- Page 32 [ITEM3] SDM Wait for ACK Time Two ASCII hex characters. The maximum time that the A75 will wait for an ACK from after an SDM was sent. After this time, if no ‘ACK’ is received, the A75 sends a PROGRESS message with the SDM Auto ACK parameter set to ‘0’. Range : 01 to 14h (20) in steps of 1 second.
- Page 33 PROGRESS (A75 to PC) Unsolicited. The PROGRESS message advises the PC of A75 status when some significant change of state in the radio occurs (typically during call processing). In Transparent mode, if TMODE Filter control is enabled with the FUNCTION command, the A75 does not generate progress messages.
- Page 34 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 A75 M2256-000-00-051 November 2001...
- Page 35 QUERY (PC to A75) The QUERY command requests the A75 to respond with data. The data can contain several types of information. [IDENT] [QUERY_TYPE] [PARAMETERS] [PARAMETER] Function [QUERY_TYPE] A single ASCII hex character representing the query type. Query Model [QUERY_TYPE] = 0 message.
- Page 36 SEND_SDM (PC to A75) The SEND_SDM command requests the A75 to send a Short Data Message (SDM). The PC sends the SDM directly to the A75, and the T201X immediately keys up the transmitter. After the specified SDM Lead In Delay the A75 sends the SDM. The SDM does not need to include a [MESSAGE] parameter.
- Page 37 S/W_VERSION (A75 to PC) Solicited. The S/W_VERSION message is sent to the PC in response to a QUERY command. It sends the version of A75 firmware in the T201X radio. [IDENT] [SW_VERSION] [PARAMETERS] [PARAMETER] Function A75 firmware version [SWVERSION] . An 8 character string identifying the A75’s firmware ver- sion operating in the T201X.
- Page 38 Transaction OK (A75 to PC) The Transaction OK is a prompt character ‘.’ (full stop, ASCII code = 2Eh) sent in Command mode by the A75 to the PC to indicate that it is ready to accept a new command. The PC must wait for the prompt before beginning the next transaction.