Appendices; Mx920 Interface Connections; Table 8-1 Mx920 Interface Connectors; Table 8-2 Mx920 Accessory Socket Pinout - RELM BK RADIO SDMX920 Technical Manual

MX920 Base Station & Repeater

8. Appendices

8.1 MX920 Interface Connections

The user connections to the MX920 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
The RJ45 pins are numbered as shown in Figure 3-4 below.
Function
Simplex relay out or
N type RX input
TX output
Microphone Socket
and RS232
Communication

Table 8-1 MX920 Interface Connectors

Table 8-2 MX920 Accessory Socket Pinout

Description
Location for internal simplex relay. The
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
The RF power output from the
transmitter for full duplex operation.
The socket provides a connection for a
microphone. Also provides RS 232
Communication between radio and PC
See Table 8-2
Comment
600ohm Z, filtered and De-emphasis.
Line level ≈ -16dbm
Current limited.
Pulled to +5V via 10k resistor. Connect
to ground for PTT.
600 ohms Z, gain and compression
functions are software controlled.
Desk Mic ≈ -43dbm
Compression enable.
Fist Mic ≈ -23dbm
Compression enable.
Pin 5 DB9M (PC RS-232).
For quiet base use. Connect to ground
for quiet base operation.
Pin 2 DB9F (PC RS-232).
Pin 3 DB9F (PC RS-232).
Technical Manual
2003 Revision