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T2000-A75 Modem

Operation Manual

© 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/

November 2001

M2256-000-00-051

Summary of Contents for T2000-A75

Page 1: ...T2000 A75 Modem Operation Manual 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 November 2001 M2256 000 00 051 ...

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Page 3: ...mode 8 Transparent mode 8 2 Changing Modes 9 3 Transparent Mode Operation 11 Transparent Mode effective data rate calculation 11 Transparent Mode RTS CTS Signalling 13 4 Command Mode Operation 17 Message Format 17 Calculating the CHECKSUM 18 Sending and Receiving Short Data Messages SDM 19 5 Commands 23 ...

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Page 5: ...d receiving responses In Transparent mode there is a direct link between the PC and the FFSK modem on the A75 Modem board and the PC sends and receives data without having to pass messages using CCDI commands Transparent mode can be set to either 9600 4800 2400 or 1200 baud between the PC and the A75 The over air data rate is either 1200 or 2400 baud The T2000 A75 modem described in this manual is...

Page 6: ...A75 modem board is fitted the T201X PGM program settings have the following constraints BCD Channel Selection should be enabled and polarity set to Normal so that the A75 can change the channel with the GO_TO_CHANNEL command Economy mode reduces the radio s power consumption when it is idle When economy mode is active and there has been no valid activity on a channel for the duration of the econom...

Page 7: ...TS signalling attributes whether the A75 sends an SDM Auto ACK after receiving an SDM and waits for an ACK after sending an SDM the Delay Time between receiving an SDM and returning an SDM Auto ACK the time that the A75 will wait for an SDM Auto ACK before sending a PROGRESS message The Transparent mode Lead In Delay time When the T201X radio receives serial data it keys up the transmitter but onl...

Page 8: ...and the FFSK modem located on the A75 The transparent link allows the PC to send and receive data without having to pass mes sages using the CCDI Command mode The transparent link is administered by the A75 which reads FFSK data arriving from another FFSK modem and sends it to the serial port Any form of binary data is acceptable but the escape sequence to switch back to Command mode should be avo...

Page 9: ...2 second idle time If the T201X defaults to Transparent mode at power up the escape character is set to the default value of Example 1 t is the message IDENT for a TRANSPARENT command telling the A75 to go into Trans parent mode 2 The SIZE parameter in this example is 01 as there is one character of data to follow in the PARAMETERS field 3 z is the escape character in the PARAMETERS field When 2 s...

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Page 11: ...tes of data is sent with a Lead In Delay of 200 ms Time to send data message block head for each block of data 1000 22 x 6 x 8 1200 x 1000 7546 ms Where 1000 bytes of data 1K bytes 22 1000 bytes 46 bytes per data block 1 block to round up to the nearest block number of block heads 6 bytes per block head 2 bytes for PREAMBLE 2 bytes for SYNC 2 bytes for block LENGTH therefore 22 x 6 total bytes in ...

Page 12: ...ome common ap plications When data is detected at the input buffer of the radio the following chain of events occurs 1 the transmitter keys up 2 a carrier is sent from the radio transmitter 3 if the receiving Base Station is set in Repeater Mode the carrier is detected and Rx Gate becomes active which in turn makes the PTT line active 4 the active PTT line keys up the transmitter This sequence is ...

Page 13: ...A75 has a 50 byte Serial Input buffer and 54 byte Serial Output buffer The PC baud is set up in the terminal program The A75 baud of 9600 4800 2400 and 1200 baud is set using the PROGRAM command It must be set to the same as the PC baud rate The FFSK over air baud of 1200 or 2400 baud is set using the PROGRAM com mand PC Terminal A70 1200 baud 1200 baud 1200 baud lead in delay RS232 over air 9600 ...

Page 14: ...nsmitter keys up it must wait for the Lead In Delay before data transfer can commence If Inhibit RTS Signal is set to 0 RTS not inhibited when an RTS signal is detected RTS on the following sequences can occur depending on the structure of the data If RTS turns off the A75 will continue to transmit until the buffer is empty and stops after the Tail Time If the buffer becomes empty while RTS is sti...

Page 15: ...stops transmitting after the transmitter time out The transmitter time out is set by the Transmit Time Duration which is set to a default of 60 seconds in the T2000 PGM programming software If the radio transmitter times out in this way it can not transmit data again unless RTS is turned off then on again Time RTS on data buffer empty RTS Inhibit 0 gap A75 PTT Tx Time RTS on data A75 PTT Tx Tx Tim...

Page 16: ...is controlled using bit 6 of the ITEM1 parameter in the PROGRAM command which sets up the configuration of the A75 If Inhibit CTS Signal is set to 1 then the CTS signal from the A75 is always on CTS hand shaking off If Inhibit CTS Signal is set to 0 CTS deactivates under the following conditions during the Lead In Delay if the PTT is pressed if the input buffer exceeds 34 bytes from a total 50 byt...

Page 17: ...ata to follow in the PARAME TERS field 3 C401060A010000BASE are the data bytes in the PARAMETERS field 4 8F is the calculated checksum of the message line 5 The actual data that is sent out the port in hexadecimal form is 23 31 32 43 34 30 31 30 36 30 41 30 31 30 30 30 30 42 41 53 45 38 46 Field Description IDENT The message identifier Identifiers are single ASCII characters lower case alphabetica...

Page 18: ...number into two ASCII hex digits MSD first Example 12C401060A010000BASE8F 1 Take the modulo 2 sum of all message bytes preceding CHECKSUM 23h 1 31h 2 32h C 43h etc therefore the modulo 2 sum is 23h 31h 32h 43h 34h 30h 31h 30h 36h 30h 41h 30h 31h 30h 30h 30h 30h 42h 41h 53h 45h 471h 2 Retain bits 0 to 7 discarding any higher order bits resulting from the summation 71h 3 Form the two s complement of...

Page 19: ...ent by the A75 after the SDM Lead In Delay SDM Auto ACK is either enabled or disabled when the modem is configured This is done in the 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 when the A75 receives an SDM it returns an ACK when the A75 sends an SDM it...

Page 20: ...ESS message of PTYPE SMD ACK 1D with the flag set to 0 No ACK Received This indicates that there is a communication fault between the modems or a fault with the second A75 2 modem The example below shows the case when both modems have the SDM Auto ACK disabled No ACK is sent or expected SDM ACK Delay Time ACK RS232 over air RS232 2 p 1D1 SIZE CHECKSUM PC 1 A75 1 A75 2 or Tait Orca PC 2 1 Lead In D...

Page 21: ...xt from the A75 SDM EE PROM When it receives the SDM QUERY command the A75 responds with a GET_SDM message If there is no data in the EEPROM then the GET_SDM is returned with an empty PA RAMETERS field The SDM CANCEL command sent to the A75 clears all SDM text from the A75 SDM EE PROM PC 1 A70 1 A70 2 SDM ACK RS232 over air PC 2 RS232 p 1E1 SIZE CHECKSUM PROGRESS SEND_SDM PROGRESS ACK Delay Time P...

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Page 23: ... received SDM data or the current call PC to A75 ERROR e A Transaction or System error message un solicited A75 to PC FUNCTION f Forces the radio to Tx or Rx or sets up Transparent Mode filtering PC to A75 GET_SDM s Gets SDM data from the radio solicited A75 to PC GO_TO_CHANNEL g Sets the T201X radio to a specific channel PC to A75 MODEL m Sends T201X radio and CCDI information solicited A75 to PC...

Page 24: ...unction CANCEL_TYPE A single ASCII hex character representing the cancelling type CANCEL_TYPE 1 Delete SDM data This will delete last received SDM text data in the A75 EEPROM If there is no valid SDM data it will do nothing Message Field Parameter Entered at terminal IDENT CANCEL c SIZE Size of parameter field 01 PARAMETERS CANCEL_TYPE 1 to delete SDM text 1 CHECKSUM Refer to the Calculating the C...

Page 25: ...rrect command letter was typed or an upper case was used ERRNUM 02 CCDI Checksum Error The checksum is not valid ERRNUM 03 CCDI Parameter Error The SIZE and PARAMETER field do not match or the PARAMETER entry was not valid ERRNUM 04 Not Used ERRNUM 05 A75 Busy Error The A75 received serial data while it was process ing a current command ETYPE 1 System error indicates that a critical system error o...

Page 26: ... as the configuration and the Transaction error CCDI Parameter Error is generated Example An example of an Error message is e03002A6 Message Field Parameter A75 Response IDENT ERROR e SIZE Size of parameter field 03 PARAMETERS ETYPE Transaction error 0 ERRNUM 02 the checksum was incorrect 02 CHECKSUM The checksum for the message string calculated by the A75 A6 ...

Page 27: ...endent upon the value of FUNCTION FUNCTION 6 TMODE Filter control enables or disables filtering out all PROGRESS messages when in Transparent mode QUALIFIER 0 disable TMODE Filter QUALIFIER 1 enable TMODE Filter FUNCTION 9 Tx Rx control forces the T201X radio into a transmitting or receiving state QUALIFIER 0 change to Rx state QUALIFIER 1 change to Tx state Message Field Parameter Entered at term...

Page 28: ...ETERS SDM_DATA 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 If there is no data available then the com mand is sent with no PARAMETERS field Message Field Parameter A75 Response IDENT GET_SDM s SIZE Size of parameter field 05 PARAMETERS SDM_DATA the SDM text message from the A75 EEPROM Hello CHECKS...

Page 29: ... 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 For a T2010 radio the valid range is 1 to 4 and for a T2015 radio the valid range is 1 to 24 Message Field Parameter Entered at terminal IDENT GO_TO_CHANNEL g SIZE Size of parameter field 02 PARAMETERS CHANNEL_NO 02 to change the radio to channel 2 The ...

Page 30: ...ype RU_TYPE 1 Conventional radio RU_MODEL A single character representing the T201X radio model RU_MODEL 2 Mobile radio RU_TIER A single character representing the T201X radio tier RU_TIER 0 for T2010 or 1 for T2015 VERSION CCDI software version A character string in the format XX XX VERSION 02 00 Message Field Parameter A75 Response IDENT MODEL m SIZE Size of parameter field 08 PARAMETERS RU_MODE...

Page 31: ...me bps as Transparent Mode Baud Bit5 Inhibit CTS signal 0 Deactivate CTS under the conditions referred to in the CTS Handshaking section 1 CTS active all the time Bit6 Inhibit RTS signal refer to RTS Signal section 0 RTS signal input is detected 1 RTS signal input is ignored Bit7 SDM Auto ACK 0 SDM Auto ACK is disabled 1 SDM Auto ACK is enabled If SDM Auto ACK is enabled the A75 sending the SDM wa...

Page 32: ...TEM5 Power up Channel Two ASCII hex characters to represent value of the channel number selected at power up Range 01 to 04 for T2010 or 01 to 24 for T2015 ITEM6 Data ID Eight ASCII hex characters to represent the radio ID used when receiving SDM data Any ASCII char is valid is the wildcard for any character e g 12 5678 Refer to the Sending and Receiving Short Data Messages SDM section Message Fie...

Page 33: ...6 Receiver Not Busy This message indicates that the receiver no longer detects an RF signal on the current channel This message is sent when the current channel becomes available PTYPE 07 PTT Mic Activated This message indicates that the PTT has been pressed This message is sent whenever the PTT is pressed in an attempt to transmit PTYPE 08 PTT Mic Deactivated This message indicates that the PTT h...

Page 34: ...Progress message is p0207C7 Message Field Parameter A75 Response IDENT PROGRESS p SIZE Size of parameter field 02 PARAMETERS PTYPE 07 the PTT mic has been activated by the FUNCTION command 07 CHECKSUM The checksum for the message string calculated by the A75 C7 ...

Page 35: ...E 0 Query Model message The T201X radio and CCDI information is returned to the PC as a MODEL message QUERY_TYPE 1 Query SDM message The SDM message is returned to the PC as a GET_SDM message QUERY_TYPE 2 Query Database message QUERY_TYPE 3 Query S W Version message QUERY_TYPE Blank Same as QUERY_TYPE 0 Message Field Parameter Entered at terminal IDENT QUERY q SIZE Size of parameter field 01 PARAM...

Page 36: ...ms of Lead In Delay is required so 00 to 04 will always be treated as 05 This corresponds to a Lead In Delay between 100 ms and 5 1 seconds in steps of 20 ms Refer to the Sending and Receiving Short Data Mes sages SDM section DATA_MESSAGE_ID SDM Data ID An 8 character string representing the SDM Data ID of the radio to which the SDM is sent It can be any alphanumeric characters is the wildcard for...

Page 37: ...W Version message is v082256A1117F IDENT v PARAMETERS SW_VERSION PARAMETER Function SWVERSION A75 firmware version An 8 character string identifying the A75 s firmware ver sion operating in the T201X Message Field Parameter A75 Response IDENT SW_VERSION v SIZE Size of parameter field 08 PARAMETERS SW_VERSION 2256A111 the T201X software version 2256A111 CHECKSUM The checksum for the message string ...

Page 38: ...arent mode The parameter sent is the escape character which is used to exit Transparent mode and return to Command mode Refer to section 2 Changing Modes for details Example An example of a Transparent message is t01zB1 IDENT t PARAMETERS ESC_CHAR PARAMETER Function ESC_CHAR A single character which is the escape character Message Field Parameter Entered at terminal IDENT TRANSPARENT t SIZE Size o...

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