M8SL2-00-002-812 T854 Optional Features G2.5
© Copyright Tait Electronics Limited August 2004. All rights reserved.
2.4 Relay Driver
A dedicated transistor (Q250) is provided for the purpose of switching an external (e.g.
coaxial) relay. The output is open collector and is activated by the Tx-Reg rail. This out-
put is available on pin 9 of the T800-03-0000 auxiliary D-range connector (D-range 2).
2.5 Local Microphone
Use of the local microphone (via the front panel stereo socket) will disable the audio
input from the line. The audio switching occurs when the PTT switch is closed.
2.6 Keying With Option PCBs
If an option PCB is fitted, the exciter may be keyed via the TX-ENB-OPT pad in the
audio processor. The line must be pulled low to key.
2.7 Transmit Key Time
(Refer to the appropriate test points and options connections drawing in Section 6 in
Part C.)
A solder link (SL501) is provided on the bottom of the PCB to allow two transmit key
time options, as shown in the table below.
*In this configuration the standby spurious emissions should be <–65dBm.
Transmit Key Time SL501
standard 30ms (approx.) not linked
short* <5ms linked
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