A common problem in customer dialling in the international automatic telephone service is the erroneous dialling of the trunk prefix of the country of destination. In the international service, this trunk prefix must not be dialled. The following measures have been tried and have proven very effective; they are recommended to reduce this problem.
ITU-T E.122-1993 Referenced Document
ITU-T E.122 Measures to Reduce Customer Difficulties in the International Telephone Service
ITU-T E.123 Notation for National and International Telephone Numbers e-mail addresses and Web addresses SERIES E: OVERALL NETWORK OPERATION TELEPHONE SERVICE SERVICE OPERATION AND HUMAN FACTORS International operation - General provisions concerning users Study Grou*， 2001-02-01 Update
ITU-T E.126 Harmonization of the General Information Pages of the Telephone Directories Published by Administrations
ITU-T E.182 Application of Tones and Recorded Announcements in Telephone Services - Series E: Overall Network Operation Telephone Service Service Operation and Human Factors - Operation Numbering Routing and Mobile Services - International Operation - Tones in Nation*， 1998-03-01 Update
ITU-T E.122-1993 history
1993ITU-T E.122-1993 Measures to Reduce Customer Difficulties in the International Telephone Service
1988ITU-T E.122-1988 Measures to Reduce Customer Difficulties in the International Telephone Service - Telephone Network and ISDN - Operation, Numbering, Routing and Mobile Service (Study Group II) 2 pp