March 2003
M2303-00-P00-805
9
4
GPS Interfaces
RS232 Interface
The RS232 interface on the despatcher radio has the following parameters which are fixed in the radio
modem firmware.
For every byte sent, there are 10 bits sent including the start and stop bits:
• Number of data bits = 8
• Parity = none
• Number of start bits = 1 (set to ‘1’)
• Number of stop bit = 1 (set to ‘0’)
The RS232 D-Range socket at the rear of the T201X radio has the following configuration:
* 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..
Note:
The start and stop bits are removed by the modem for the over-air transmission of data. The FFSK data
sent is pure binary 8 bit data only.
Connections
Function
Connections
Function
1
Not used
6
T2002-A00 supply
2
TXD
7
RTS
*
3
RXD
8
CTS
*
4
T2003-A00 supply
9
Not used
5
GND