ITU-T E.131-1993 PDF

Scope: Many Administrations are planning to introduce supplementary telephone services which are likely to be viable only if controlled by the user (a list of possible supplementary telephone services is given in Supplement No. 1 at the end of this fascicle). It is therefore necessary to consider means of providing users with procedures by which such control can be achieved. The purpose of this Recommendation is to prevent an undesirable proliferation, in various countries, of subscriber control procedures for such services. Descriptions are given below of three control procedures schemes now in use or in various stages of evolution. Guidelines are offered to Administrations planning to offer subscriber controlled supplementary services. Reference is made to Annex A for a glossary of terms used in this Recommendation.

ITU-T E.131-1993 Referenced Document

ITU-T E.131 Subscriber Control Procedures for Supplementary Telephone Services
ITU-T E.161 Arrangement of Digits Letters and Symbols on Telephones and Other Devices that can be Used for Gaining Access to a Telephone Network Series E: Overall Network Operation Telephone Service Service Operation and Human Factors International Operation - Number*， 2001-02-01 Update

1993 ITU-T E.131-1993 Subscriber Control Procedures for Supplementary Telephone Services
1988 ITU-T E.131-1988 Subscriber Control Procedures for Supplementary Telephone Services - Telephone Network and ISDN - Operation, Numbering, Routing and Mobile Service (Study Group II) 8 pp