Service features describe the functionalities supported by the telecommunications services. A telecommunications service is described by the totality of its service features or switching features.
Service features can be divided into general connection features, basic service features and supplementary service features. Connection features include service-specific characteristics such as the number of channels, the transmission rate, and the type of switching technology. The basic service characteristics describe the properties for information transmission such as connection establishment and termination, communicationconfiguration, protocols and character sets used, etc. In addition, the IP communications server maintains statistical information about connection frequency, utilization, current status of the connection, etc., and accounting.
- In ISDN, a distinction is made between normal service features and additional service features. The normal service features include the multiple subscriber number( MSN), extension dialing for PBX systems( DDI), switching on the bus( TP), caller ID display( CLI) and caller ID suppression ( CLIR). Euro-ISDN also has other service features that are also offered by Telekom. These include destination number indication, destination number indication suppression, subaddressing( SUB), subscriber-to-subscriber signaling, call charge indication, call forwarding ( CD, CFNR), and call forwarding( CF, CFB, CFU), caller identification, call waiting( CW), closed user group (CUB), call hold( CH), three-party conference ( 3PTY), call forward ing (CF) during call phase, callback on busy (CFB), and conference call( CONF) for conference calls.
- Digital cellular networks support most of the known service features, but also offer additional service features that are important for mobile communications. A distinction is made between normal and additional service features. Normal service features include multiple call numbers, extension dialing in the case of PBXs, plugging in at the bus, display of the call number at the destination device, and suppression of the call number display at the recipient. Additional service features include destination number display, suppression of destination number display, subaddressing, subscriber-to-subscriber signaling, call charge display, call forwarding and call forwarding, caller ID, call waiting, closed user group, call hold, three-party conference, call forwarding during the call phase, busy callback, and conference calling.