Shared call appearance (SCA) is a feature of VoIP systems that allows various devices to share one identifying line number, and lets users merge functionality for multiple devices. With shared call appearance, users can direct a telecom company to put the same line extension on a mobile device, a desktop phone or various other multiple devices.
Part of the value of shared call appearance is to allow for a more consistent user experience for inbound callers. Documentation of some ISPs’ shared call appearance features shows that any extension to which the shared call is presented can answer the phone when it rings. In some systems, there is also the ability to put a line on hold and answer it from some other device on the same shared call appearance list. Companies use shared call appearance to enhance the caller's journey through their phone systems.