Hold

Most PBXs can associate multiple sessions with a single line. A call session can be placed on a hard hold, which frees the user's line/address to make other calls.

The call on hold is temporarily disconnected, allowing the application to use the line device for making or answering other calls. The hold operation performs a so-called "hard hold" of the specified call (as opposed to a "consultation call"). A call on hard hold typically cannot be transferred or included in a conference call, but a consultation call can. Consultation calls are initiated using conference or transfer operations.

After a call has been successfully placed on hold, the call state typically transitions to onhold. A held call is retrieved by an unhold operation. While a call is on hold, the application can receive messages about state changes of the held call. For example, if the held party hangs up, the call state can transition to disconnected.

In a bridged situation, the hold operation may not actually place the call on hold. The status of other stations on the call can govern (for example, attempting to "hold" a call when other stations are participating is not possible); instead, the call can simply be changed to the inactive state while it remains connected at other stations.

Not all service providers support use of this operation.

TAPI 2: lineHold, lineUnhold

TAPI 3: ITBasicCallControl::Hold