MCEF
Mobile Station Memory Capacity Exceeded Flag
A part of the MWI (Message Waiting Indication) to be stored in the HLR (Home Location Register). MCEF indicates if the address list of MWD (Message Waiting Data) contains one or more entries where SMS delivery has failed because the memory capacity of the subscriber’s SIM (Subscriber Identity Module) or USIM (UMTS Subscriber Identity Module) is exceeded.