User Manual Part 1

MAINTENANCE AND SERVICE
16 MM101271V1 R2A
• RemAudioFlag - Digital TTL active low input, diode isolated
This is the Remote Audio Present indicator. This line, when low, indicates that
remote audio from the IMC is present. This is generated by the base station in
response to 2175Hz or E&M from the IMC.
• FSL - Digital open drain bi-directional
output: 300-mA sink (low), 10mA source (high)
input: Zin = 1k ohm
This is the bi-directional Frame Sync Line. The line is used as an output in the
Control Channel and as an input in the Working Channel.
• ADCin – Analog input
level = 0 to 5 volts, Zin = 100Kohm
This is the 8-bit Analog to Digital Converter (ADC) input. This may be used to
monitor station PA power.
5.3.2 Simulcast Control
• ext_PTT - Digital TTL active low input, diode isolated
This is the external source for Local PTT and is only active in a Simulcast
configuration.
• ext_A/Dmodctrl - Digital TTL active low input, diode isolated
This is the external source for the Analog/Digital modulation control and is only
active in a Simulcast configuration.
• ext_150 - RS422 input
This is the external source for Low Speed Data and is only active in a Simulcast
configuration.
• ext_9600baud - RS422 input
This is the external source for High Speed Data and is only active in a Simulcast
configuration.
• bypass - Digital TTL active low input, diode isolated
This is the Simulcast bypass control signal. This line, when low, forces the site to
operate in non-Simulcast mode and is driven by the Simulcast control equipment.
• inhibit - Digital TTL active low input, diode isolated
This signal is the Simulcast alarm indicator. This line, when low, indicates the
presence of a Simulcast alarm and is driven by the Simulcast control equipment.
• txclk_in - Digital TTL active low input, diode isolated
This is the external source for High Speed Clock and is only active in a Simulcast
configuration.
• txclk_alarm - Digital TTL active high output
This signal is the Simulcast Tx Clock alarm indicator. This line, when high, indicates