Cn6 Simplex Relay; Cn7 Tx Output; Smx920 Test Points; Table 8-3 Smx920 Test Points - RELM SMX920 Technical Manual

SMX920 Base Station & Repeater

8.1.1 CN6 Simplex Relay

This option maybe also pre-installed or retrofitted at a later date. The N type
connector for the RX port is removed and the relay is mounted in it's position, which
then acts as the RF I/O port for simplex operation. When this option is installed the
radio programming will required to be change to reflect the simplex mode.

8.1.2 CN7 TX Output

This is an N type connector used as the TX RF power output.
8.2

SMX920 Test Points

TP Function
1 Discriminator
2 Limiter output
3 15Volts VCO Supply
4 8 Volts Supply
5 PA Refl Volts
6 P\A Fwd Volts
7 5volt Supply
8 W/B | N/B Control Line
9 Tx Drive Power control
10 RSSI Volts
11 Rx Enable
12 PA PTT
13 Rx Lock Detect
14 Rx VCO Volts
15 Rx STB
16 Tx Lock Detect
17 Mute Control Pin To IC1/P81
18 PA Temp Volts
19 PTT
20 Tx VCO Volts
21 Tx Enable
22 VCO Modulation
23 Reference Osco Modulation
24 Tx PLL Strobe
25 Tx & Rx PLL Data
26 PLL Clock
27 Mic VF Audio Compressor
28 13.8 V Supply
32
Test
Points
Volts
2.5V
15.5V
8V
<200mV
0-5V
5V
5V OR 0V 5V Wide, 0V Narrow Band Mode
0-12V
0-5V
5V
0V
5V
2-14V
0V
5V
0V
5V
2-14V
5V
0V
3Vp-p
13.8V

Table 8-3 SMX920 Test Points

Technical Manual
Notes/ Condition
1Vp-P RX Audio
TX Audio Limiter output
Supply Rail For VCO Control Volts
Regulator Output IC38
>1V bad VSWR
Approx 2.8V @ 50Watts
5V Regulator Output
12V Maximum exciter RF power
Rx Enable
PA PTT Enable
RX PLL Is In Lock
Voltage Depends On Frequency
Idle State, 5V When Strobe
TX PLL Is In Lock
Mute Open
PTT Enable
Voltage Depends On Frequency
Tx Enable
Modulation
Modulation
Idle State, 5V When Strobe
Data line for PLL
PLL Clock
Full Compression
13.8V Supply Input After Fuse
Point.
RELM/ BK RADIO