CES SUPPORT 407-679-9440
Page 11
MAN79 © CES 2009
Pin 9- PTT Common
Most transmitters require a ground for transmitter keying , in this case connect pin 9 to ground. In cases where
positive voltage is required for keying, connect this pin to the appropriate voltage source.
Pin 10- Aux. NO
(optional)
Pin 11- Aux. NC
(optional)
Pin 12-
(Not used)
Pin 13- External COR Input
This connection is optional. The RM-20 can determine the presents or absents of a carrier either by its internal
squelch circuit (see pin7 RX Audio) or the External COR Input. If squelched or filtered audio will be used for the
RX Audio connection, then this connection will be required. Connect this input to a point in the receivers squelch
circuit that changes state when the radio is receiving a signal (squelch is open). This signal must be a DC change
that swings between 1 volt or lower to 3 volts or higher. The active state of this input is programmable.
Pin 14-Ground
(same as pin 8)
Pin 15- 12V DC
Connect to a source of regulated, filtered 12VDC supply. If separate power supplies are used for the transmitter and
receiver units, the power source for the RM-20 should be the one used to power the receiver. This will lessen the
chance of problems due to voltage fluctuation when the transmitter keys and unkeys.
Note:
Pins 3, 10, and 11 are the auxiliary relay contacts. This programmable relay can be used to control external
circuitry. A pre-programmed code will enable and disable the relay over the air. To program a code refer to the
programming section in this manual.
2.11 Interconnect Interface J1- DB-9
The RM-20 provides an interconnect interface connector on the rear panel (pin by pin compatible with our model
4700VP). Following is a list of pins and functions of J1.
Pin 1
Push to Talk
Pin 2
RX Audio
Pin 3
Interconnect mode
Pin 4
N/C
Pin 5
Ground
Pin 6
TX Audio
Pin 7
TX Disable
Pin 8
COR
Pin 9
12 V DC
