EMEA IP Office Technical Tip

034: Clarification of the "CallListen" Feature

24th November 2003 - Full PDF Text Version


When a call listen attempt is made from any telephone handset to an IP hard phone, the call listen attempt will be unsuccessful. This affects all IP Office software versions, where IP hard phones are used.

The reason for this is that the "Call Listen" function is not supported upon IP terminals. This is due to limitations within the packet stream on the 46xx terminal.

However, a "Call Intrude" will work, as both conversations are conferenced before the voice stream is packetised. With "Call Listen", the caller is trying to intrude on one side of the voice path only, rather than both (two way speech); this is not achievable with an IP voice stream.