User Manual Part 1

MAINTENANCE AND SERVICE
MM101271V1 R2A 15
• LocPTT - Digital active low open drain output
This signal is the Local PTT control. This line, when low, will key up the base station
transmitter and select the local receiver audio source for transmission.
• RemPTT - Digital active low open drain output
This signal is the Remote PTT control. This line, when low, will key up the base
station transmitter and select the remote audio source for transmission.
• A/DmodCtrl - Digital output TTL
This is the Analog/Digital Modulation Control signal. When high, HSD is routed to
the base station transmit. When low, LSD/audio is routed to the base station transmit.
• HSAcq - Digital output open drain output
This is the High-Speed Acquisition control signal. A high or low signal produces a
corresponding high or low time constant in the limiter circuit.
• LocRxMute - Digital active low output (8.5 volt low Z source)
This signal is the Local Receiver Mute control. This line, when low, blocks the
routing of receiver audio to the base station transmitter and line out. Muting occurs
during HSD transmission, no valid carrier present, or no valid LSD present.
• Walsh1/Walsh2 - Digital output TTL
These two signals are combined to form a two bit Walsh Function DAC. This signal
is the Low Speed Data source.
• Synth_Clk – Digital open drain output
This signal provides the clock source for loading the base station frequency
synthesizer (required for MIIe). Data is clocked on the negative edge of the clock.
The baud rate is approximately 2.4Kbaud.
• Synth_Data – Digital open drain output
This signal provides the data source for loading the base station frequency
synthesizer (required for MIIe). Data is clocked on the negative edge of the clock.
The baud rate is approximately 2.4Kbaud.
• Synth_LdEn – Digital open drain output
This signal is the Synthesizer Load Enable control. This line, when high, permits the
base station frequency synthesizer to be loaded and is used for protection against
invalid transitions on the clock and data lines.
• Synth_Locked – Digital TTL active high input
This is the Synthesizer Locked signal. This line, when high, indicates that the base
station synthesizer is locked. This is used for verifying successful synthesizer loading
and is also continuously monitored as a failure mode.
• PAFail - Digital TTL active high input diode isolated with pull-up
This is the Power Amp Failure indicator. This line, when high, indicates that the base
station PA has failed. A floating line asserts PA Fail.