I
IETF – Internet Engineering Task Force
IFAST – International Forum on ANSI-41 Standards Technology
IIF – Interworking and Interoperability Function
IMS – IP Multimedia Subsystem
IMSI – International Mobile Subscriber Identity
IMSI 11 12 – Same as MNC (Mobile Network Code)
IMSI S – Short IMSI, Mobile Identification Number
Inbound Roamer
Industry Organizations
INF – Industry Negative File
Interconnection
Inter-standard Roaming
IRM – International roaming MIN
IS-2000 - Superseded by TIA-2000
IS-41 - Superseded by TIA-41
IS-835
IS-856 - Superseded by TIA-856
IS-95
ISG – International Signaling Gateway
ISUP – Integrated Services User Part
ITU - International Telecommunications Union
Read more about this topic: List Of CDMA Terminology