Hi Rod,
If you use Plantronics Headsets there is a "Y" cord made specifically for this purpose.
"Y" Training Adapter
The Y training cable allows you to connect two headsets with QD (Quick Disconnect) connections to one phone. It also includes a mute switch which allows you to mute either headset.
This adapter is compatible with the following products:
QD amplifiers, such as the M12, M10, M22, MX10, M12 LUCM, A20, and S20
Polaris headsets
DA series adapters (for USB ports)
Avaya/Lucent HIC and HIP cables
It is not compatible with the S12 or any cordless/wireless products. (A CA10 with a 2.5mm to QD adapter cable is the only exception.)
The part number for the Y training adapter is 27019-03.
There are 2 versions of the Y training adapter. The difference is the version of the QD locks in the package.
27019-03 has 62976-01 - Latest version of the Quick Disconnect (QD) lock
27019-01 had 29733-01 - Older version of QD lock
If you have an older style of QD connection (which has a flat edge rather than a semi-circle at the end), the Y cord for those versions of QD has been obsolete and is no longer available. They were part number 21847-01 (for SSI) and 21847-02 (Supra) and they also did not have a mute switch.
Cord,âYâ
Training
QD to QD
27019-03
http://plantronics.custhelp.com/cgi-bin/plantronics.cfg/php/enduser/std_adp.php?p_faqid=186&p_created=979856369&p_sid=n3Wgk-Pi&p_accessibility=0&p_redirect=&p_lva=&p_sp=cF9zcmNoPTEmcF9zb3J0X2J5PSZwX2dyaWRzb3J0PSZwX3Jvd19jbnQ9OTgmcF9wcm9kcz0mcF9jYXRzP...
Hope this helps!
Rob