350-Watt Digital VHF LB Transmitter
Chapter 2, System Description, Maintenance &
Remote Control Connections
DT325B, Rev. 0
2-10
Signal Name
Pin
Designations
Signal Type/Description
RMT AUX IO 1
TB30-4
Discrete Open Collector Inputs, Discrete Open Drain
Outputs, or 0 - 5 VDC Analog Input - When used as an
output, this line is pulled to +5 VDC with a 1.0 kO resistor
for logic high and pulled to ground for a low. A diode
allows this line to be pulled up to 12 VDC. When used as a
digital input, this line considers all values over 2 Volts as
high and those under 1 volt as low. As an analog input,
this line is protected by a 5.1 Zener diode.
RMT RF System
Interlock
TB30-5
When this signal's circuit is completed to ground the
transmitter is allowed to operate. Typically, a jumper is
connected from TB30-5 and TB30-15. If this circuit is
opened, the transmitter switches to a Mute condition.
(See note at end of table)
RMT
Transmitter
Operate
TB30-6
Discrete Open Collector Input - A pull down to ground on
this line indicates that the transmitter is to be placed into
the operate mode.
RMT
Transmitter
Stand-By
TB30-7
Discrete Open Collector Input - A pull down to ground on
this line indicates that the transmitter is to be placed into
the standby mode.
RMT Power Raise TB30-8
Discrete Open Collector Input - A pull down to ground on
this line indicates that the transmitter power is to be
raised.
RMT Power
Lower
TB30-9
Discrete Open Collector Input - A pull down to ground on
this line indicates that the transmitter power is to be
lowered.
RMT
System Reflect
Power
TB30-10
Analog Output - 0 to 4.0 V- This is a buffered loop through
of the calibrated “System Reflected Power” and indicates
the transmitter's reflected output power. The scale factor
is 25 % / 3.2V.
RMT System
Forward Power
TB30-11
Analog Output - 0 to 4.0 V- This is a buffered loop through
of the calibrated “System Average Power”. Indicates the
transmitter's Average power. Scale factor is 100 % / 3.2V.
RMT Spare 1
TB30-13
Remote connection to spare module - Use is TBD.
RMT Spare 2
TB30-14
Remote connection to spare module - Use is TBD.
Interlock Rtn
TB30-15
Typically connected to TB30-5, which allows the
transmitter to operate.
+12 VDC
TB30-16
(Connects to triple peak detector board, the isolation
relay board, and the VHF amplifier tray.)
+12 VDC w/
2 Amp re-settable fuse
Rtn
TB30-17
(Connects to the VHF amplifier tray.)
Rtn
-12 VDC
TB30-18
(Connects to isolation relay board.)
-12 VDC w/ 2
Amp re-settable fuse.
Power Lower
TB30-19
Discrete Open Collector Input - A pull down to ground on
this line indicates that the transmitter power is to be
lowered.
Rtn
TB31-1,2,6-11
Rtn
RTN Ground
TB31-12
(Connects to triple peak detector board.)
Ground
System Reflect
Power
TB31-13
(Connects to triple peak detector board.)
Analog
Input - 0 to 1.00 V- This is the input of the “System
Reflected Power ” indicating the transmitter's reflected
output power. The scale factor is 25 % / 0.80V.
