Batboard

Hello again all....

Would it be at all possible for someone with a Centracom manual to fax or scan the page that shows how the headset connector is wired? It should be in every Centracom manual, and I desperately need a schematic of how its wired to adapt some backup consoles.

I would be happy to PayPal $10 to whomever could send me the info. I got a diagram from Plantronics, but it is of very limited help.

PM or post a reply here and I'll be in touch. Thanks for any help!

If what you want is the wiring of the headset plug itself, that's easy.

The headsets have a pair of 1/4" plugs.

The jack can be wired for either 'four wire' or 'six-wire' headsets.

The transmit audio is across the two TIPS.
The receive audio is across the two SLEEVEs.
The PTT switch is across the two RINGS.


Four wire headsets usually don't have the sleeve connections so if a four wire headset is plugged into a jack that is set up for six-wire - the longer sleeve part of the plugs will short out the ring contacts in the jack causing PTT to be activated.


A picture of a SINGLE 1/4" phone plug that shows the TIP / RING / SLEEVE for identification can be found here:

http://www.aeroelectric.com/articles/mi ... cjack.html

And here is a headset jack box that takes the dual tip-ring-sleeve plugs:

http://www.twacomm.com/Catalog/Model_GB ... KNLEK4BUJA

xmo wrote:If what you want is the wiring of the headset plug itself, that's easy.

The headsets have a pair of 1/4" plugs.

The jack can be wired for either 'four wire' or 'six-wire' headsets.

The transmit audio is across the two TIPS.
The receive audio is across the two SLEEVEs.
The PTT switch is across the two RINGS.


Four wire headsets usually don't have the sleeve connections so if a four wire headset is plugged into a jack that is set up for six-wire - the longer sleeve part of the plugs will short out the ring contacts in the jack causing PTT to be activated.


A picture of a SINGLE 1/4" phone plug that shows the TIP / RING / SLEEVE for identification can be found here:

http://www.aeroelectric.com/articles/mi ... cjack.html

And here is a headset jack box that takes the dual tip-ring-sleeve plugs:

http://www.twacomm.com/Catalog/Model_GB ... KNLEK4BUJA

Great information, thank you. I have been looking for a source for the boxes. I *think* there may be more to it, though, which is why I want to take a look at a Centracom manual page. The fax I just got from Plantronics indicates that there are active electronics in box the headset and the PTT box, which they call a "push-to-key amplifier."

Specifically, on this diagram of the SHS-1890 (the amplfier/ptt box), it shows:

Some kind of op-amp looking device going to the two tips, the sleeves go all the way through to the headset, and the two rings as the PTT. That jives with what you documented, with the exception of the tips. It seems like they must get power in some way to bias the mic?!

Any ideas?

There is 'more to it' so if you are looking to duplicate the way Motorola interfaces to the headset you probably still want to see the Centracom schematics.

The Motorola headset jack box contains active circuitry. It is supplied with 15 VDC from the operator position electronics. It biases the mic and buffers the transmit audio going back top the op position.

It also has a receive audio amp and level controls for two audio inputs - phone and radio.

xmo wrote:There is 'more to it' so if you are looking to duplicate the way Motorola interfaces to the headset you probably still want to see the Centracom schematics.

The Motorola headset jack box contains active circuitry. It is supplied with 15 VDC from the operator position electronics. It biases the mic and buffers the transmit audio going back top the op position.

It also has a receive audio amp and level controls for two audio inputs - phone and radio.

Thanks again. I thought that I might need the associated manual pages to understand it, and you've definitely confirmed that. Now only to find them!

Many thanks.