464
TMAA01-01 Line-Interface Board
TM8100/TM8200 Service Manual
© Tait Electronics Limited
June 2006
The comparators (in U1) operate off a single sided regulated 5V supply.
U1 pins 2,4 and 5 provide receiver gate delay. Once the busy signal is not
active, C4 charges through R12 and causes U4 to go low. Once charging
exceeds the voltage at U1 pin5. This also locks out the keying state until this
delay has occurred (U6 pin 5).
17.8.3
Data Communication
The Line Interface circuitry is designed to provide RS-232 and RS-422 data
communication. RS-232 is provided by U9, but if RS-422 is required, U9
is removed and replaced by U2 and U10. Also resistors R15,16,43 and 47
need to be fitted.
17.8.4
Power Supply
The power supply for the line-interface board comes from the radio via
the internal options connector and is a 13.8 V switched supply. Digital
logic components are used in the line-interface board so there is a 5 V
regulator provided.
Initially the 13.8V from the radio is filtered and used for the audio line
driver (U5) with reference to analogue ground. This 13.8V is also used to
supply the 5V regulator, which is filtered separately for either 5V digital or
analogue devices. A simple voltage divider is used to provide a 2.5V half-rail
for the digital and a 2.2V rail for the analogue sections.
Summary of Contents for TM8235
Page 1: ...TM8100 mobiles TM8200 mobiles Service Manual MMA 00005 04 Issue 4 June 2006...
Page 10: ...10 TM8100 TM8200 Service Manual Tait Electronics Limited June 2006...
Page 62: ...62 Description TM8100 TM8200 Service Manual Tait Electronics Limited June 2006...
Page 148: ...148 Disassembly and Reassembly TM8100 TM8200 Service Manual Tait Electronics Limited June 2006...
Page 162: ...162 Servicing Procedures TM8100 TM8200 Service Manual Tait Electronics Limited June 2006...
Page 178: ...178 Interface Fault Finding TM8100 TM8200 Service Manual Tait Electronics Limited June 2006...
Page 258: ...258 Receiver Fault Finding TM8100 TM8200 Service Manual Tait Electronics Limited June 2006...
Page 446: ...446 Spare Parts TM8100 TM8200 Service Manual Tait Electronics Limited June 2006...