Tait TM8200 mobiles, Руководство по аксессуарам

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28 TMAA01-01 Line-Interface Board TM8100/TM8200 Accessories Manual
© Tait Electronics Limited August 2005
The comparators (in U1) operate off a single sided regulated 5 V 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).
2.8.3 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.
2.8.4 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 5 V regulator, which is filtered separately for either 5V digital or
analogue devices. A simple voltage divider is used to provide a 2.5 V half-rail
for the digital and a 2.2V rail for the analogue sections.