​Study Group 2 is home to the numbering standard ITU-T Recommendation, E.164, which has played a key role in shaping the telecom networks of today. E.164 provides the structure and functionality for telephone numbers, and without it we would not be able to communicate internationally. In recent years SG2 has worked on ENUM, an Internet Engineering Task Force (IETF) protocol for entering E.164 numbers into the Internet domain name system (DNS).

A less well-known, but equally as important product of SG2 is E.212 which describes a system to identify mobile devices as they move from network to network. International mobile subscriber identity (IMSI) is a critical part of the modern mobile telecoms system allowing a roaming mobile terminal to be identified in another network and subsequently for querying of the home network for subscription and billing information to take place.

SG 2 is home to two groups made-up of network operators. The service and network operations group (SNOg) aims to make sure that the operations staff - often at the frontline of any telecommunication service provider - needs are taken into account in the development of standards. And the quality of service development group (QSDG), aims to define QoS parameters for network operators and their customers.

With work on next generation networks (NGN) spanning all ITU-T study groups, SG2 is expected to play a key role in the defining the operational aspects of interworking between traditional – circuit-switched – telecommunication networks and evolving – NGN or packet-switched networks.

Also in SG 2 much work is done on standards in support of telecommunications for disaster relief. The ITU-T Rec. E.106, International Emergency Preference Scheme for disaster relief operations (IEPS). The prioritization of calls in a disaster situation means that in an emergency, telecoms networks can be effectively cleared of non-urgent calls.