This part is a little more complex since it has an 27C64 Eprom programed like this:

D0 - Morse code. ( 1 = beep, 0 = Pause )

D1 - PTT on.

D3 - Reset flag for the morse timers.

This is quite straightforward, The 2 bottom 12 bit counters are conected in a series, the 2 counters are used to set the interval between the beacon´s identification, this interval is selectable by setting 4 dip-switches. 

When all inputs of U19A become high, U19A sets the first cascaded flip-flop enabling the start of adress counter U11, U11 starts counting only if the translator is not in use by any station, U6a receives this information at pin 4 ( high if used by any station ), if this is low ( not in use ) then the count begins, since the condition for starting the beacon is only valid for 1 clock pulse the flip-flop U6B ( lower flip-flop ) has a closed loop so it will remain locked low until D2 of the Eprom becomes high reseting the counters and flip-flops. The pulsed output hight states produced by the Eprom D0 will activate the beacon oscilator to produce the beep´s, this signal is then mixed and injected to the radios. D1 us used for setting the 2 transceivers PTT on so that the beacon is transmitted on both bands at the same time.