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
This is the time this page has been accessed since since 24 Feb 2001.