Yealink SIP-T23P User Manual page 59

You can use two headsets when enabling dual headset. To use this feature, you must
physically connect headsets to the headset jack and handset jack respectively. Once
the phone connects to a call, the headset connected to the headset jack will have
full-duplex capabilities, while the one connected to the handset jack will only be able to
listen.
To 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.
Note
Dual headset is configurable via web user interface only.
There are two types of DSS keys: Line Keys and Programmable Keys. The details will be
introduced in the following. The SIP-T23(P/G) IP phone supports 3 line keys.
You can assign predefined functionalities to the line keys to have quick access to
features such as call return and voice mail. The line key LEDs will indicate status when
the keys are assigned with particular features, such as BLF . The default key type of each
line key is Line.
Customizing Your Phone
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