User's Manual

This input is the square wave from the receive tone filter and comparator, U300-A. This waveform would
normally be a square wave version of a received QC or DQC tone/signal.
Pin 11 SPKR EN
This output enables the audio gate which drives the audio PA for speaker audio. It is active low when
speaker audio is to be present.
Pin 12 REPEAT AUDIO EN
This output enables the audio gate which routes receive voice audio to the transmit audio chain. It is active
low when audio is to be routed to the transmitter.
Pins 13, 14 Not Used
Pin 15 BEEP/ID TONE LSB
This output is the least significant bit of a two bit output for generating tones to be transmitted.
Pin 16 EEPROM Enable
This output is used to control the U309, the memory IC.
Pins 17, 18 SQUELCH
This input is the output of U300-B. It is high when a valid carrier is detected. Note that this input
considers only the presence of a carrier, not whether the correct signaling tone is present.
Pin 19 MON
This input is from J300, pin 4 and is low when it is desired to have speaker audio present. The unit will not
transmit when this input is taken low, even if a valid signal is received or the PTT line is taken low.
Pin 20 RX LD
This input is the receiver synthesizer lock detect output. It is high when the receive synthesizer is in lock.
Pin 21 TX LD
This input is the transmit synthesizer lock detect output. It is high when the transmit synthesizer is in lock.
This would be the normal state for transmit, but this input should be low otherwise.
Pin 22 GROUND
Pin 23 Not Connected
Pin 24 DATA
This output is the data line from the microcontroller to the various peripherals in the Repeater, including
the memory IC and the synthesizer IC’s.
Pin 25 TX SYN EN