This is a very handy device if you work with U-229 type audio accessories. Instead of trying to hold test meter probes on top of the U-229 connector pins, you can just calmp them using the U106U Silver spring clips. There are 5 wires in this unit, so it is not good if you are working with the newer 6 pin connectors. The Ground U106U has a balck rubber boot installed so that it is easy to find. The terminals are marked:
A = GND
B = REC
C = MIC BUTTON
D = MIC
E = RING
Many of the modern military radios use the 6 pin AUDIO connectors that take the U-329/U plug. By replacing the U-229/U 5 pin plug and using a cable with more conductors (Alpha Wire AE p/n 1176C, 6 cond, #22) and replacing the scoket this audio test adapter can be used for work with 6 pin AUDIO accessories. To make it more useful an on-off-(on) switch was added from the C "PTT" pin to ground. The "(on)" position is momentary and in the "on" position the radio is continously keyed, a handy feature that saves one hand.
The added "F" terminal is used by the PRC-68B, -126, -128 and -136 for the channel frequency assignment digital data up and down loads. It turns out the the PRC-6725 & PRC-139 use pin "E" for digital data and they do not have a provision for external DC power on pin "E" like the Magnavox squad radios.
This modification is really handy when working with the various fill and data modes of the U-229 family of equipment.
The top is marked G.R.M Corp, 13567. A DLIS CAGE lookup on that number returns ITT Night Vision?.
Telegenix Inc. (formerly knows as Grim or G.R.M. Corp) -
Top View - there is a black rubbr cap
on the A ground terminal
Side image showing three of the U106U spring clips.
These can be found at American-MilSpec
and occasionally on eBay
Back to Brooke's Photo of Military Audio Accessories,
Military Audio, PRC68.COM,
Squad Radio, Military
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