Plantronics RJ11 headset not working with Cisco 8851 phones

[openfield2010]

Having a lot of issues getting headsets working in the headset socket on the Cisco 8851 phones.  Tried multiple headsets across multiple phones and still not resolution, any ideas?

The headsets that do work at the minute are Plantronics HW251, they're old ones that go through a Plantronics Vista box which converts them to RJ11, before going into the headset RJ11 port on the back of the phone.  All of the new RJ11 headsets that we've purchased, which includes headsets that go straight to RJ11 and a Plantronics HW251 with a quick disconnect adapter to RJ11, doesn't work when plugged into the headset port i.e. no dial tone when pressing the headset button and caller can't hear the headset user either.  Plugging headset into the rj11 handset connector on the phone, the headset will work absolutely fine as long as you lift the handset.

Any ideas?

[Jonathan Schulenberg]

Based on your statement that some older headset models work, I assume the  Product Specific Configuration Field to disable the headset port has not been checked.

Usually the headset manufacturer has a compatibility toggle switch with various settings per-manufacturer. If that is set incorrectly it won’t work - consult Plantronics documentation for the correct Cisco setting.

[openfield2010]

Thank you for the response.

Just a quick update.

I've tried a couple of converters, both the Vista box and another Plantronics quick connect to rj11 adapter, and these both work absolutely fine with the headset into the headset port on the back of the 8851 phone. 

So essentially what i have now is 2 different quick connect to RJ11 adapters where both of them work fine when plugged into the handset connection on the back of the 8851, but only one of them works when plugged into the headset connection.  Both look to be exactly the same adapter, the newer one has slightly thinner cabling, both work fine in the handset port, only old one works in the headset port.  I've gone through the phone config for my phone and the headset options are enabled for the phone on the CUCM server.

[Jonathan Schulenberg]

The only configuration option that exists on Cisco phones is to outright disable the headset port. Clearly the port isn't disabled since it works with some things. Baring a highly unlikely hardware DSP failure in the phone, this would seem to be an incompatibility with the Plantronics accessory. I suggest reaching out to Plantronics support.

[Rob Huffman]

Hi there,

Just wanted to add a note to the good tips from my friend Jonathan.

If you look closely at the RJ11 ends on the working vs non-working quick disconnect cords you will likely see a wiring difference. You will need the part number listed below.

I believe the required cord is actually the U10 (the U10 is used with almost all Cisco phone models) rather than the A10 which is likely the non-working cord. You can check via the Plantronics compatibility guide;

Coil Cord to QD Modular Plug

Model: U10

Part Number: 26716-01

http://www.plantronics.com/ca/compatibility-guide/#/detail/?key=sku6790027sku4230017

Cheers!

Rob