Connecting Older Wireless Headsets to Polycom Phones with a 2.5mm Plug to Modular Cable

Over a year ago, Plantronics designed a couple of electronic hook switch (EHS) cables to connect their wireless headsets to many of the Polycom phones instead of using the traditional handset lifter.  Unfortunately, there are a few models (IP320, 321, 330, 331) where it’s impossible to connect the headset or EHS cable directly to the phone, due to the fact that their headset jack is a round 2.5mm instead of the modular (square) RJ9.

Polycom has designed adapter #2200-11095-002 to connect headsets and cables that have the RJ9 jack, including Plantronics wireless headsets, and their APP-51 and APP-5 EHS cables.  But you have to buy them in quantities of five or more.  Is there something different?  Well, the new wireless headsets (e.g. CS540) need to use the adapter.  The older wireless headsets (e.g. CS50, CS70N, CS351N, CS361N) can use the 2.5mm Plug to Modular Cable #78333-01 from Plantronics along with the APP-5 EHS cable to connect to the Polycom phones listed above.  So, how do you use these cables together when connecting the older wireless headsets to the phone?  Let’s take a look.

1) You’ll notice that the APP-5 EHS cable has four connectors.  The modular RJ9 and a 90° 3.5mm adapter are on one end, the modular RJ9 and a 5 pin adapter on the other.

2) You insert the 90° 3.5mm adapter to the bottom of the CS50 (or similar) base, into the open round jack next to the A.C. cord.  On the back of the Polycom phone you insert the multi-pin adapter into the jack next to where the handset is connected (there’s only one place where it will fit).

3) The two loose modular RJ9 connectors remain unattached.

4) Insert the modular end of cable 2.5mm Plug to Modular Cable into the modular jack on the bottom of the wireless headset base, indicated by a telephone symbol.  The 2.5mm end on this cord plugs into the 2.5mm headset jack on the side of the Polycom phone, indicated by a headset symbol.  You’re now ready to enjoy the freedom of a wireless headset.

Remember: Your phone may need some programming for the headset to work properly and these instructions only apply to connecting older CS wireless headsets to the Polycom phones listed above.  For further assistance contact the Headsets Direct sales/service center at 800-914-7996.

For more information see: Plantronics 2.5mm Plug to Modular 78333-01

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