User's Manual

Jotron AS| TR7750C: Operators Manual  Installation
Page 4-13
P/N: 84748 (G)
 ALARM_P, ALARM_N (AUX1, pin 1 and 2)
This is a differential signal, used to signal the alarm state. The radio can be set up with an
internal pull-up to +12V if desired.
 ALARM (REM, pin 7)
Same as the signal above, but this signal is referenced to GND.
 SELECT (AUX1, pin 3 and 6)
This input is connected to an optocoupler. The SELECT requires an external voltage to
operate.
One way to use the SELECT signal is in conjunction with the ALARM output signal from
another radio unit. If the ALARM signal (ALARM_P and ALARM_N) on a primary (main) radio
is connected to the SELECT_P and SELECT_N on a secondary (backup) radio, then automatic
switchover from the main to the standby radio is performed when the main radio detects an
alarm. In this mode, a pull-up is required on the ALARM output from the primary radio.
Menu path:
Interface
config ►
Parameter
Range
Default
Details
Alarm config
(TX and RX)
Alarm pin pull-up
Disabled |
Enabled
Enabled
The ALARM_OUT_P and ALARM_OUT_N
output pins on AUX1 is used to signal that
the radio has an alarm. This parameter
applies a pull up voltage to ALARM_OUT_P
when there are no alarms present. When an
alarm is detected the relay contact close.
Alarm config
(TX and RX)
Select polarity
High | Low
Low
The SELECT_IN_P and SELECT_IN_N
input pins on AUX1 can be used to select /
deselect (Standby) the radio with an
external signal (e.g. alarm from a main
radio). This setting determines if the radio
should be operational on a low select input
signal or a high select input signal.
Table 4.6-8, Alarm and Select settings, transmitter and receiver