Call completion

From Wikipedia, the free encyclopedia

Call Completion is a telephony feature allowing some form of alternative interaction between parties who cannot converse directly with each other. There are several possible factors which can prevent a call from connecting successfully:

User does not answer
User is busy in another call
User is offline/unavailable
User actively disconnects the call before answering

There are various definitions as to what exactly constitutes Call Completion. Generally speaking, Call-Completion may encompass the following services:

The rational for providing these features is that allowing some sort of communication between parties unable to talk directly serves both the interests of the callers (allowing them to exchange information despite the inability to talk), as well as the Telecom operators, as the service allows them to get some return for providing the resources for the call (whereas if the caller simply hangs up, the operators basically have provided the call resources with no return).

Call Completion features can be implemented on a PBX (e.g. Call Hold/ Transfer), dedicated server (e.g. a Voicemail Server) or directly on the client device (e.g. Messaging applications).

There are several commercial companies which provide Call Completion features, as well as IETF documents specifing Call-Completion features for open standards, such as SIP.