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Appendix E Testing with the TBA0STU Calibration Test Unit
TB9400/TN9275 Installation and Operation
© Tait International Limited May 2023
Checking Digital Output LEDS 1 and 2
These LEDS are connected to DIO1 and DIO2 and will light if the outputs
are active low.
There are no switches connected to DIO1 and DIO2, so alarms and task
builder applications using these inputs cannot be tested with the CTU.
Notice
There is a central ground banana socket that is 19.6mm
(0.75”) spacing from the RX gate, TX relay, TX Key and RSSI connec-
tors to enable a dual banana plug to be used for signal output and
ground. The banana sockets on each system IO can be used for timing
and other tests of the base station.
Monitoring RX Gate Output
An LED will indicate when the RX gate output has activated, the RX gate
output is active low.
RX Gate only works in analog mode.
Checking RSSI Levels
A voltage proportional to the received RF signal level is available on this
output.
RSSI is the only output that is functional in analog, P25 and DMR modes.
Checking TX Relay
An LED will indicate when the antenna (simplex) relay is active. From
version 3.25 firmware (and later) this output can be accessed as digital
output 13 on TaskBuilder.
This is only an output and has no input circuitry associated with it.
TX Relay works in analog and P25 modes.
Using TX Key
A switch is available to key the transmitter on. A banana socket is also
available for keying from an external input.
TX Key only works in analog mode.
