| CN | CN1 | CN2 | CN3 | CN4 | CN5 |
| CT | CT1 | CT3 | CT4 | CT5 | CT6 |
| GERAN | GERAN1 | GERAN2 | GERAN3 | GERAN4 | GERAN5 |
| RAN | RAN1 | RAN2 | RAN3 | RAN4 | RAN5 |
| SA | SA1 | SA2 | SA3 | SA4 | SA5 |
| T | T1 | T2 | T3 |

TSG Core Network and Terminals (TSG CT)

Overview:

The TSG Core Network and Terminals (TSG CT) is responsible for specifying terminal interfaces (logical and physical), terminal capabilities (such as execution environments) and the Core network part of 3GPP systems. More specifically: User Equipment - Core network layer 3 radio protocols ( Call Control, Session Management, Mobility Management), signalling between the core network nodes, interconnection with external networks, O&M requirements, GPRS between network entities, Transcoder Free Operation, CAMEL, Generic User Profile, Wireless LAN - UMTS interworking and descriptions of IP Multimedia Subsystem, SIP Call Control, SDP protocols for the IM subsystem, mapping of QoS and the interfaces specific to the UMTS Open Service Access (OSA).