Ranger Communications Texas Ranger TR-127DX, Service Manual

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2.4 ALTERNATE MICROPHONES AND INSTALLATION
For best results, the user should select a low impedance dynamic type microphone or a transistorized
microphone. Transistorized type microphones have a low output impedance characteristic. The
microphones must be provided with a four-lead cable. The audio conductor and its shielded lead
comprise two of the leads. The third lead is for transmit control and the fourth is for receiving control.
The microphone should provide the functions shown in the schematic below (Figure 2-3).
4 WIRE MIC CABLE
Pin Number Mic Cable Lead
1 Audio Shield
2 Audio Lead
3 Transmit Control
4 Receive Control
Figure 2-3 Your Transceiver Microphone Schematic
Figure 2-4 Microphone plug and pin numbers viewed from rear of pin receptacle.