PTT Wiring - Making sure

[pvalovich]

-8A with a Stark-wired panel. PMA7000B with 3 mic wires: PTT, Audio and Lo. I understand how to wire them to the mic jack. But I also have dual Infinity grips with 2 wires coming from the trigger PTT switch. Do I wire these in parallel to the PTT and Audio tabs on the mic jack?

[Mike S]

Seeing as how Stark wired the panel, I suggest you talk to them.

What I am used to seeing is PTT to Lo, however that may not be what Stark did----or maybe it is.

Check with them.

[az_gila]

Originally Posted by pvalovich

-8A with a Stark-wired panel. PMA7000B with 3 mic wires: PTT, Audio and Lo. I understand how to wire them to the mic jack. But I also have dual Infinity grips with 2 wires coming from the trigger PTT switch. Do I wire these in parallel to the PTT and Audio tabs on the mic jack?

Any (all) of your PTT switches should just ground the PTT line. So yes... wire them in parallel...

gil A

CORRECTION

Your PMA 7000 B does not have split transmission capability, but the PTT to the pilot and co-pilot are separate, and care must be taken not to mix them up.

This enables the logic in the audio panel to disconnect one mic. when the other person is transmitting.

So just wire the appropriate jack PTT line to the infinity switch, and set it up so the stick switch is a switched connection to ground.

Full PMA 7000 B details are here....

http://www.ps-engineering.com/docs/PMA7000B_IM.pdf

[AltonD]

Lo is ground

[Mike S]

Originally Posted by AltonD

Lo is ground

IIRC, Lo is the ground provided internally inside electronic boxes like radios and intercoms etc.

By using a local ground instead of the Lo line, you increase your chances of inducing a ground loop, and noise into the audio system.

Re read my prior post-------PTT to Lo, not PTT to ground.

Also, unless the radio and intercom are completely hooked up, you may not be able to trace out the Lo line with an ohm meter, as the Lo circuit passes through some intercoms---------as I found out when hooking up my panel.

[az_gila]

My description should have stayed as "parallel" for the PTT connections.

I assume the Infinity PTT switches are independent, and neither side is connected together or to ground in the stick... is that correct?

To clarify, connect the Infinity PTT switches in parallel to the appropriate mic jack. This is the way the PM schematic shows it. They are not shown as shielded in the PM IM so a twisted pair will be fine.

See pages 31 and 32 of this PM document

http://www.ps-engineering.com/docs/PMA7000B_IM.pdf

gil A