ZETRON 4000 Series, Installation Manual

Page: 71 / 418

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Wiring to the Channels
Push-to-Talk +/-
The dry contacts across these two signals close whenever the channel is transmitting. This
may be used for a single function, local transmitter keying, or E&M signaling. The
contacts will handle 1A at 48V. While the PTT contacts are closed, the “XMIT” indicator
on the channel card is on.
Carrier Operated Relay +/-
Normally, the console derives its call indication from a VOX circuit connected to the Rx
Audio. However, for a more positive call indication, this signal may be connected to a
local transceiver’s carrier operated relay (COR) circuit. This may also be used in E&M
signaling systems. Note that the voltage from COR+ to COR- must be between 5 and 20V
to indicate “CALL ON”, and between 0.7 and 0 to indicate “CALL OFF”. A negative
voltage or a voltage greater than 25V should never be placed across the COR inputs.
While COR is indicating “CALL ON”, the CALL indicators on the channel card and the
"CALL" text in IntegratorRD are active.
Auxiliary Output
This open-collector output pulls to ground when the standby-base feature for the channel
is activated. This output will sink 500 mA to 0.8V when active, and will withstand no
more than 12V when inactive.
Transmit Audio +/-
This is the balanced source for transmit audio. Normally, the impedance of this output is
600  , however, with the replacement of a jumper, this output can be set to 3500  when
not actually sourcing audio. This can be useful for paralleling control stations on the same
set of wires. The output is isolated for voltages up to 1500 VAC. The transmit audio level
may be adjusted as high as +10 dBm using the “TX” adjustment on the channel card.
The Tx Audio signals are also used for receiving audio in a 2-wire system. The 2-wire
receive sensitivity may be adjusted to -30 dBm using the “2W RX” adjustment on the
channel card.
Receive Audio +/-
This is the balanced input for receive audio in a 4-wire system. Normally, the impedance
of this input is 600  , however, with the replacement of a jumper, this input can be made to
go to 10,000  when not actually sourcing audio. This can be useful for paralleling
multiple control points. The output is isolated for voltages up to 1500 VAC. The 4-wire