International Telecommunications Personal Correspondence Service (ITPCS) is an obscure ITU

Itu

Itu is an old and historic municipality in the state of São Paulo in Brazil. The population in 2009 was 157,384 and the area is 641.68 km². The elevation is 583 m. This place name comes from the Tupi language, meaning big waterfall. Itu is linked with the highway numbered the SP-75 and are flowed...

 proposal regarding the allocation of country code +991 for use in some form of individual-based international numbering plan. It may have been intended as a space for ENUM

Enum

ENUM or enum may refer to:* E.164 NUmber Mapping, a suite of protocols to unify the telephone system with the Internet* An enumerated type, a data type consisting of a set of named values...

 trials, as the ITU allocated the range +991 001 to Neustar

NeuStar

Neustar, Inc. is a provider of clearinghouse and directory services to the global communications and Internet industries.-History:Neustar was incorporated in Delaware in 1998. It started as a business unit within Lockheed Martin Corporation...

 for use in an ENUM

Enum

ENUM or enum may refer to:* E.164 NUmber Mapping, a suite of protocols to unify the telephone system with the Internet* An enumerated type, a data type consisting of a set of named values...

 trial in 2002. However, the most recent approved ENUM trial, with Telesoft's Sentiro, was allocated space in the UPT

Universal Personal Telecommunications

Universal personal telecommunications is a special segment of the international telephone number space which has been set aside for universal personal telephone numbers. This service has been allocated country code +878. UPT numbers differ significantly from Personal Numbers which are embedded as...

range (country code +878). No other allocations have been reported in the +991 space.