User Guide for the SIP-T21(P) E2 IP Phone50To enable dual headset via web user interface:1. Click on Features->General Information.2. Select Enabled from the pull-down list of Dual-Headset.3. Click Confirm to accept the change.NoteThere are two types of DSS keys: Line Keys and Programmable Keys. The details will beintroduced in the following. The SIP-T21(P) E2 IP phone supports 2 line keys.You can assign predefined functionalities to line keys. You can also define a label for aline key feature which will appear on the LCD screen. Line keys allow you to quicklyaccess features such as recall and voice mail. The line key LEDs will indicate themonitored status when the line keys are assigned with particular features, such as BLF.The default key type of each line key is Line.To assign functionality to a line key via phone user interface:1. Press Menu->Features->DSS Keys.2. Select the desired DSS key, and then press the Enter soft key.3. Select the desired key type from the Type field.4. (Optional.) Select the desired key event type from the Key Type field.Dual headset is configurable via web user interface only.