This is the Plantronics CS500 and Savi series APC-42 (replaces APC-41) Electronic Hookswitch (EHS) cable for Cisco IP Phones - communicates electronically with the phone, eliminating the need for old mechanical HL10. the APC-42 is only compatible with these Plantronics wireless headset models:

Plantronics CS510, CS520, CS530, CS540, Savi WO100, WO200, WO300, WO350, W710, W720, W730, W740, W745.

APC-42 is exactly the same as previous APC-41, except it's now compatible with Cisco 6945

This EHS adapter only works with the following Cisco IP Phones:

Cisco 6945, 7821, 7841, 7861, 7942G, 7945G, 7962G, 7965G, 7975G, 8811, 8841, 8851, 8961, 8961, 9951, 9971

If you have Cisco IP 8961 9951 9971, you need the APU-71 instead

If you have Cisco 8941, 8945, 8945G use Plantronics APC-82 instead

Note: Do not order this part if you don't have the listed Cisco phone models

Cisco phone software requirements

• The Cisco server must be running Cisco CallManager System Version 4.1(3)SR5x or higher. Verify by logging onto the Callmanager with a browser. Press the detail button on the main page to display the SW version.
• The Cisco phone must be running firmware 8.3(3)x or higher. To locate the firmware version, press the Settings button on the phone (the checkbox icon). Select “Model information”. The firmware revision is listed under “Load File.”

Cisco phone setup

• The phone must be set for “Wireless Headset Hookswitch Control” = Enabled
• Press the settings button on the phone (Checkbox Icon). Select “Device Configuration” >> Select “Media Configuration”
• If “Wireless Headset Hookswitch Control” is “Disabled”, follow the instructions below

Enabling Cisco wireless headset EHS hookswitch control:

Access the server administrator with a browser. Select Device>Phone through the drop down menus. Click "Find" with no selection criteria to obtain a list of all phones
Open the desired phone. Scroll down to "Wireless Headset Hookswitch Control" Set to "Enabled" Click "Apply". Wait for the dialog box to appear, then reset the phone by clicking the reset button.
 

If your Cisco phone is equipped with the Cisco 7914, 7915, 7916 expansion module:

• Plug the expansion module into the telephone AUX connector.
• Connect the APC-42 into the expansion module.
• Use 85638-01 / 40287-05 adapter to extend the APC-42 audio input to reach the headset jack on the phone.