Call Waiting is a feature that allows you to receive a call while you are already on the line with someone else.
For example, User A and User B are on the phone, User C make an incoming call to User A, at this time, User A will receive a sound prompt "du...du...", at the same time, you can choose answer, reject or hold the new call.
1. Both IP Phone and PBX extension have call waiting feature, but we don't suggest you enable these on both sides at same time. The PBX extension's priority is higher than IP Phone, because call waiting on PBX is earlier triggered.
2. If call waiting is enabled in PBX, "when busy" call forwarding option will be disabled.
3. We don't suggest to enable call waiting on PBX and GSM module of TG-Series products. As it is not supported.
Call Waiting Feature of PBX
To simplify the call process handled by PBX, SIP/IAX extension has removed call waiting option after version 220.127.116.11. If you want to use this feature, just enable it on the IP Phone side. While FXS extension still have this option.
Call Waiting Feature of SIP Terminal
1. IP Phone (Yealink phone for example)
Path: Features>General Information
2. Linkus extension
Path: Me>Setting>Call Options