Wiring Help

[ninjamedic2293]

Ok guys I need some help. I am working on an interesting project of mine and want to adapt a standard civilian helicopter headset/helmet to work on a Jedi series radio, specifically an XTS5000. The civilian helicopter intercom system uses 600 ohm speakers (2 - 300 ohm speakers wired in series I believe), and an electret microphone with an unknown impedance. It terminates in a U-174/U plug with the pinout below. I plan on making an intermediate cable with the Jedi terminal on one end and a small PTT box with female U-174/U plug on the other. I am very comfortable with the wiring but not as sure about making the impedance correct etc. and I was hoping that the great wiring geniuses on this forum could help me out.

U-174/U Pinout

Tip = +MIC
RING1 = +AUDIO
RING2 = -MIC
RING3 = -AUDIO

[chartofmaryland]

If this is to be relied on for flight communications, I would look to David Clark for help as this is not something a half baked wiring job should be used for.

Not that your intentions are good, just sometimes the best needs to be used. Although the PRICE is hard to swallow.

If this is not for flight comms then you will have a job ahead of you as there are levels that need to match that make the PTT and mic audio function properly.

I have had luck in tearing apart a speaker mic and using the PCB from the internals to then wire in a mic and speaker output where I then used the cord to mate to the radio.

You have to watch the loading unless you are using the factory speaker and mic, I had to use two transformers to match loading before I could wire in other types.

CoM

[escomm]

Dallas Avionics makes kits for Motorola mobiles that have the transformers built in, I suspect they have something that would work for the portables too.

[mruwave]

When I first started flagging for the SCCA, I didn't particularly care for the brand of headsets they used. They have an analog multichannel system, conventional tone PL in / DCS out on VHF. I 'eBayed' a decent looking David Clark headset. The earpieces are 300 ohms each. I paralleled them together for a 150 ohm headset speaker impedance and purchased an electret mike from David Clark because I wanted to take advantage of the noise cancelling capability. I use Hirose 6 pin connectors on the headset and beltpack PTT box and a pigtail from the box to the radio (P1225 or GP300). I use an old Motorola multiconductor coiled cell phone cord from the headset to the box. With the P1225 and GP300, simply connecting the mike to the input is sufficient to place the radio in transmit, but I paralleled a 1.5K 1/8 W resistor across the mike for insurance. In listening to the recordings, my radio sound as good as or better (in all respects) as the track radios. I have Formula cars passing within 30 feet of me and my radio is perfectly clear.
If the mission is critical, go to Motorola or David Clark, but don't be afraid to experiment.

[welshtorg01]

Was a solution ever obtained for this? I have a similar issue.

[redpilotjon]

I am making the same thing for our helicopters. I have a lot of information that might help you.

I have the pinout for the XTS 5000 accessory connector and some other information.

Email me at jonathan.noble1@us.army.mil

I'm trying to attach a pdf to the site but can't.