Modification
of Motorola MC
Micro for PTT output.
1. Opto
4N32 "belly up", pin 4 to GND.
2.
Connect 4N32 pin 2 to pin 9 on
U704.
3.
Connect 4N32 pin 1 to 9.6 VDC
via 1K resistor.
4. Cut
connection to VR651.
5. Cut
link L--M, and connect 4N32 pin
5 to L (pin 9 on J5).
This
PTT-output (open collector) is
controlled by the microprocessor, and detects if a valid PL-tone is
received, and will not open with only a carrier, if PL-squelch is
enabled.
