Specifications

SMX920 Base Station & Repeater Technical Manual
RELM/ BK RADIO
32
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
Test
Points
TP Function Volts Notes/ Condition
1 Discriminator 2.5V 1Vp-P RX Audio
2 Limiter output TX Audio Limiter output
3 15Volts VCO Supply 15.5V Supply Rail For VCO Control Volts
4 8 Volts Supply 8V Regulator Output IC38
5 PA Refl Volts <200mV >1V bad VSWR
6 P\A Fwd Volts 0-5V Approx 2.8V @ 50Watts
7 5volt Supply 5V 5V Regulator Output
8 W/B | N/B Control Line 5V OR 0V 5V Wide, 0V Narrow Band Mode
9 Tx Drive Power control 0-12V 12V Maximum exciter RF power
10 RSSI Volts 0-5V
11 Rx Enable 5V Rx Enable
12 PA PTT 0V PA PTT Enable
13 Rx Lock Detect 5V RX PLL Is In Lock
14 Rx VCO Volts 2-14V Voltage Depends On Frequency
15 Rx STB 0V Idle State, 5V When Strobe
16 Tx Lock Detect 5V TX PLL Is In Lock
17 Mute Control Pin To IC1/P81 0V Mute Open
18 PA Temp Volts
19 PTT 5V PTT Enable
20 Tx VCO Volts 2-14V Voltage Depends On Frequency
21 Tx Enable 5V Tx Enable
22 VCO Modulation Modulation
23 Reference Osco Modulation Modulation
24 Tx PLL Strobe 0V Idle State, 5V When Strobe
25 Tx & Rx PLL Data Data line for PLL
26 PLL Clock PLL Clock
27 Mic VF Audio Compressor 3Vp-p Full Compression
28 13.8 V Supply 13.8V
13.8V Supply Input After Fuse
Point.
Table 8-3 SMX920 Test Points