Appendices; Smx920 Interface Connections; Table 8-1 Smx920 Interface Connectors; Table 8-2 Smx920 Accessory Socket Pinout - RELM SMX920 Technical Manual

Technical Manual

8. Appendices

8.1 SMX920 Interface Connections

The user connections to the SMX920 are all made via the Front and rear panel where
the following connectors are located.
No Conn Type
CN6 N TYPE
CN7 N TYPE
SKL RJ45
Pin No Function
1 Low level muted RX VF
2 +8V DC
3 Microphone PTT
4 Microphone VF
5 EARTH common
6 Hook / Monitor switch
7 RS-232 RxD
8 RS-232 TxD

Table 8-2 SMX920 Accessory Socket Pinout

The RJ45 pins are numbered as shown in Figure 3-4 below.

Figure 8-1 RJ45 socket viewed from front of SMX920

RELM/ BK RADIO
Function Description
Simplex relay out or Location for internal simplex relay. The
N type RX input antenna for RX / TX connects to this
point. Alternatively a N-Type
connector can be used for the input to
the receiver for full duplex operation
TX output The RF power output from the
transmitter for full duplex operation.
Microphone Socket The socket provides a connection for a
and RS232 microphone. Also provides RS 232
Communication Communication between radio and PC
See Table 8-2

Table 8-1 SMX920 Interface Connectors

Comment
Filtered and De-emphasis.
Current limited.
Pulled to +5V via 10k resistor. Connect
to ground for PTT.
600 ohms Z, gain and compression
functions are software controlled.
Pin 5 DB9M (PC RS-232).
For quiet base use. Connect to ground
for quiet base operation.
Pin 2 DB9M (PC RS-232).
Pin 3 DB9M (PC RS-232).
1 .................. 8
Installation and Operation
31