The Wiki of Unify contains information on clients and devices, communications systems and unified communications. - Unify GmbH & Co. KG is a Trademark Licensee of Siemens AG.
There are different categories of headsets:
- Corded headsets
- Cordless (DECT or Bluetooth base station connects via cable to the phone)
- "pure" Bluetooth headsets
The best audio quality is provided when using corded headsets, plugged directly into the 4/8 pin (121 TR9-5/*) headset socket of the phone (ask the headset supplier to get the right (adapter) cable for your headset which fits directly into the OpenStage or Desk Phone IP headset socket).
Connecting a headset to the handset cord (via external amplifier) is not a recommended configuration, from a functional and acoustical perspective.
Corded headsets are typically equipped with a 4-pin western plug. Cordless headsets (resp. their base stations), if they support the electronic hook switch functionality (EHS), do have an 8-pin western plug (to transport the signalling). No handset lifter is needed with OpenStage / Desk Phone IP. The OpenStage / Desk Phone IP socket supports both western plugs without any adapter, since the socket is hardware coded so that the 4-pin western plug does not rock around. This hardware coding also prevents, that someone plugs in a standard RJ45. Meaning, the headset 8-pin western plug is not a standard RJ45 (which could be a PoE powerd LAN cable).
The following wired headsets are recommended for use at any phone with a wired headset connector.
Bluetooth is available on OpenStage 60/80 and OpenScape Desk Phone CP600/700/700X.
How to configure and use Bluetooth headsets with our phones is described in the user manual of the phone.
These headsets have been certified with our desktop phones. Please also visit our Technology Partner homepage with certificates and test reports: 
In particular please have a look to our support page from our partners: