GSM-Codes allow you to setup advanced settings like;Forwarding - The iPhone only has one call forwarding option: a forward all callsa and you cannot set call forwarding if busy or if not answered or when iPhone is off.Call Barring - Enables you to restrict or bar certain or all types of calls to and from your mobile phone, i. e. outgoing calls, outgoing international calls, incoming calls.Other settings:- SMS with Delivery Report- Missed Call Alerts- Personal Voicemail Number What's new