jotron RA-7203C, Operator'S Manual

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Jotron AS| TR7750C: Operators Manual

Installation Page 4-9
P/N: 84748 (G)
4.6.3 Other key signals
Figure 4.6-2, Key signals on the transmitter unit
In addition to the line loop keying, it is possible to key the transmitter, using several other hardware
and software options.

TX_KEY_G
This is a signal available on the transmitter REM connector, pin 4. This signal, if connected to
GND will key the transmitter.

TXKEY_P, TXKEY_N
This is a differential signal, available on the transmitter AUX2 connector, pin 7 and 8. This
signal will key the transmitter if a voltage between 12 and 48 V is fed between them. Note
also that this is a differential signal, not connected to any ground potential inside the
transmitter, therefore the signal can be configured for both positive and negative voltage
keying (see figure).