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Article ID: 000026468
Last Modified Date: 05/17/2021
Access Level: Public

APC-4/APC-40/APC-41, APC-42, APC-43 (Cisco EHS Cable): How to Install

EHS Installation
This procedure explains how to install the APC-4/APC-40/APC-41/APC-42/APC-43 EHS cable, which is compatible with the following Cisco phone models:

-6945    -7841
-8841    -7861
-8845    -7942G
-8851    -7945G
-8861    -7962G
-8865    -7965G
-7821    -7975G

*NOTE: The APC-43 replaces the cables APC-40, APC-41, and APC-42.
Software Requirements
  • The Cisco server must be running Cisco CallManager System Version 4.1(3)SR5x or higher. Check with your telephone administrator to verify this.
  • The Cisco phone must be running firmware 8.3(3)x or higher. To find your firmware version, press the Settings button on the phone (the checkbox icon). Select "Model information." The firmware revision is listed under "Load File."
Phone Settings
The phone must have
  • "Headset Enabled" = Yes
  • "Headset Hookswitch Control" = Enabled.
To verify this:
  1. Press the Settings button on the phone (the checkbox icon). Select "Device Configuration" > "Media Configuration."
  2. If "Headset Enabled" is "No" and/or "Headset Hookswitch Control" is "Disabled," contact your telephone administrator.
Expansion Module Information
If the phone is equipped with a 7914, 7915, or 7916 expansion module:
  1. Plug the expansion module into the telephone AUX port.
  2. Plug the APC-4/APC-40/APC-41/APC-42/APC-43 into the expansion module.
  3. Use a Part Number 85638-01 (formerly 40287-05) adapter (sold through our distributors) to extend the APC-4/APC-40/APC-41/APC-42/APC-43 audio input to reach the headset jack on the phone. Click here to view the setup.
To Install the EHS Cable
  1. Connect your EHS cable to your phone and on your base, set your compatibility switch, speaking and listening volumes to the following:
    Image of the set up of the APC-43 on a Cisco phone.

Earlier Models
Click here for installation instructions for CS50/CS55/CS60/CS70/CS70N/CS351N/CS361N using the APC-4, configuration settings can be found here.

Click here for a full compatibility guide