GSM Services - Supplementary Services

Supplementary Services

See also GSM codes for supplementary services.

• Call forwarding.
• Barring of Outgoing Calls.
• Barring of Incoming Calls.
• Advice of Charge (AoC). This service estimates the call cost for display on the user's mobile phone. This helps users by preventing bill shock and reduces the load on the mobile network operator's customer service department. However, in practice, this service is rarely used because the calculation is more complex than the standard allows. Instead, some operators provide SMS based balance and call cost notifications subscribers at the end of a call.
• Call Hold.
• Call Waiting.
• Multiparty service.
• Calling Line Identification presentation/restriction.
• Closed User Group (CUG).
• Explicit Call Transfer (ECT). This service allows a user who has two calls to connect these two calls together and release its connections to both other parties.