making/modifying a PTT handset

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eahuntley

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I'm interested in putting together a PTT handset(like are used with some military field radios). For discussions sake, we'll say I want to use it with my Vertex VX-2200. The VX-2200 uses an 8-pin modular plug identical to that of the FT-450.

My initial thought here is to just use a PTT handset for a different radio and attempt to add the correct connector to fit my radio, but I'm not sure if that's possible. I know there would need to be audio coming out of the modular jack, but I'm not certain if there is. I DO know that I use the modular jack to program the radio(via a computer), does that mean I have audio going both ways through that jack?

Are there any other reasons why this wouldn't work?

Here's one of the handset's I'm talking about, in case anyone doesn't understand.
2 - U.S. Military Radio Handset H-250/U for PRC NEW - eBay (item 180621682484 end time Feb-11-11 18:06:47 PST)
 
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davidgcet

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programming is digital data, so not a way to tell about audio.

however, here is the pinout per the service manual:

Pin 1 is hook, this is grounded to tell it you are "on hook"
Pin 2 is NOT USED/NOT CONNECTED
Pin 3 is PTT
Pin 4 is TX Audio
Pin 5 is Ground
Pin 6 is 8V
Pin 7 is CL-Sw
Pin 8 is CL-Data

i don't see any RX audio on the jack. though you might could frog it over inside the unit to pin 2 since it is not connected. the rest are used for programming or mic functions.
 

eahuntley

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Darn. I was afraid of that. When I get home tonight Maybe I'll pull out all the manuals for my other mobile radios and see if any of them have RX audio on the jack. I might look into diverting the audio over to pin 2, but that might be a little out of my league.

While I was searching earlier I actually found a brand new H-250/U(the type handset I linked to) for $20 including shipping, so I couldn't pass it up.

This page has the pinout for the H-250/U. The connector is listed as U-182B/U, U-229/U: MilSpec Communications: Military Radio Accessories


programming is digital data, so not a way to tell about audio.

however, here is the pinout per the service manual:

Pin 1 is hook, this is grounded to tell it you are "on hook"
Pin 2 is NOT USED/NOT CONNECTED
Pin 3 is PTT
Pin 4 is TX Audio
Pin 5 is Ground
Pin 6 is 8V
Pin 7 is CL-Sw
Pin 8 is CL-Data

i don't see any RX audio on the jack. though you might could frog it over inside the unit to pin 2 since it is not connected. the rest are used for programming or mic functions.
 

W2NJS

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The fastest, simplest way to make a PTT handset is to use a standard telephone-type unit which has a PTT bar installed on the inside of the bridge between the receiver and transmitter. Usually the switch comes out with just a couple of small hex screws and you rewire it for ground and PTT. On the transmitter unit Atlas Sound makes a drop-in dynamic replacement unit that requires no power and has an impedance of about 500 ohms. For the receiver you can use the standard telephone unit without changes. If the ground is common to the PTT, mic and receiver units you should be able to do this with only four wires. One thing to watch out for when buying a used PTT handset is to be sure that the tx and rx screw on covers actually come off. If the unit has been used in a security system, such as prison, the custom is to glue the covers on and once that's done you'll never get them off.
 
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