Implementing a Transmit Inhibit line on the IC-7610

by Adam Farson VA7OJ/AB4OJ. Based on research by Marty Sullaway NN1C.


The External Keypad feature for the IC-7610 is documented on p. 13-4 of the IC-7610 Basic User Manual. The keypad is connected to the rear-panel [EXT KEYPAD] jack via a 3.5mm TRS (tip-ring-sleeve) plug, as shown in the schematic below and on p. 13-4 of the Basic manual.

To enable the external keypad and MUTE function, turn ON the following menu item:

MENU SET > Connectors > External Keypad

The mute switch is connected between Ring and Sleeve of the TRS plug, as shown. The mute switch inhibits transmit and receive functions. The rest of the keypad circuitry is needed only if full keypad functionality is desired.

External keypad with MUTE switch. Courtesy Icom Inc.
External keypad with MUTE switch. Courtesy Icom Inc.

Last updated: 03/10/2019