MT-4E VHF & UHF Receiver & Transmitter Instruction Manual
IM08-MT-4E-TXRX-P1162
VHF & UHF Hardware Tuning and Troubleshooting
21
48-PIn MotHERBoaRd IntERFaCE ConnECtoR
A 48-pin connector is used for interfacing the MT-4E Motherboard to the receiver and transmitter.
Receiver
Pin Name
Pin Name
Pin Name
d2
Relay normally open 1 [o/P]
B2
+13.8 vdC [I/P]
z2
+13.8 vdC [I/P]
d4
Relay Common 1 [o/P]
B4
Receive Secure / Clear* [o/P]
z4
no Connect
d6
Relay normally Closed 1 [o/P]
B6
+9.5 vdC [I/P]
z6
+9.5 vdC [I/P]
d8
Relay normally Closed 2 [o/P]
B8
no Connect
z8
no Connect
d10 Relay Common 2 [o/P]
B10 discriminator lPF [o/P]
z10 no Connect
d12 Relay normally open 2 [o/P]
B12 CoR* [o/P]
z12 CoR* [o/P]
d14 Clear keys 1* [I/P]
B14 discriminator [o/P]
z14 Squelch override* [I/P]
d16 Clear keys 2* [I/P]
B16 no Connect
z16 no Connect
d18 no Connect
B18 no Connect
z18 Bank a/B* [I/P]
d20 Channel Select 0 (lSB) [I/P]
B20 SM-3 Speaker audio [o/P]
z20 no Connect
d22 Channel Select 1 [I/P]
B22 no Connect
z22 no Connect
d24 Channel Select 2 [I/P]
B24 Signal Strength (RSSI) [o/P]
z24 Rx Mode [o/P]
d26 Channel Select 3 (MSB) [I/P]
B26 Balanced audio 1 [o/P]
z26 Balanced audio 2 [o/P]
d28 no Connect
B28 Mute* [I/P]
z28 no Connect
d30 no Connect
B30 Ground
z30 Ground
d32 no Connect
B32 Ground
z32 Ground
transmitter
Pin Name
Pin Name
Pin Name
d2
no Connect
B2
+13.8 vdC [I/P]
z2
+13.8 vdC [I/P]
d4
no Connect
B4
Microphone audio output [o/P]
z4
Microphone audio Input [I/P]
d6
no Connect
B6
+9.5 vdC [I/P]
z6
+9.5 vdC [I/P]
d8
no Connect
B8
Isolated Positive Ptt [I/P]
z8
Isolated negative Ptt [I/P]
d10 no Connect
B10 Ptt* [I/P]
z10 Ptt* [I/P]
d12 no Connect
B12 Bank a/B* [I/P]
z12 Bank a/B* [I/P]
d14 Clear keys 1* [I/P]
B14 Ptt* [I/P]
z14 Ptt* [I/P]
d16 Clear keys 2* [I/P]
B16 no Connect
z16 no Connect
d18 no Connect
B18 Balanced audio 2 [I/P]
z18 Balanced audio 1 [I/P]
d20 Channel Select 0 (lSB) [I/P]
B20 SM-3 Speaker audio [I/P]
z20 no Connect
d22 Channel Select 1 [I/P]
B22 Subtone [I/P]
z22 a*/d Mode Control [I/P]
d24 Channel Select 2 [I/P]
B24 Ptt output* [o/P]
z24 transmit Secure / Clear* [I/P]
d26 Channel Select 3 (MSB) [I/P]
B26 Forward Power alarm* [o/P]
z26 High vSWR alarm* [o/P]
d28 no Connect
B28 no Connect
z28 direct Modulation
d30 no Connect
B30 Ground
z30 Ground
d32 no Connect
B32 Ground
z32 Ground
* Indicates an active low signal.
