This Recommendation applies to digital local, combined, transit and international exchanges for telephony in Integrated Digital Networks (IDN) and mixed (analogue/digital) networks, and also to local, combined,transit and international exchanges in an Integrated Digital Networks (ISDN).The field of application of this Recommendation is more fully defined in Recommendation Q.500.Some measurements only apply to a certain type (or types) of exchange.
ITU-T Q.544-1988 Referenced Document
ITU-T E.230 Chargeable Duration of Calls (Study Group I) 4 pp*， 1992-01-01 Update
ITU-T E.277 Conventional Transmission of Information Necessary for the Collection of Charges and the Accounting Regarding Collect and Credit Card Calls - Telephone Network and ISDN - Operation@ Numbering@ Routing and Mobile Service (Study Group II; 1 pp; Same as Recm*， 1989-01-01 Update
ITU-T E.401 STATISTICS FOR THE INTERNATIONAL TELEPHONE SERVICE ( NUMBER OF CIRCUITS IN OPERATION AND VOLUME OF TRAFFIC )*， 1993-01-01 Update
ITU-T E.427 COLLECTION AND STATISTICAL ANALYSIS OF SPECIAL QUALITY OF SERVICE OBSERVATION DATA FOR MEASUREMENTS OF CUSTOMER DIFFICULTIES IN THE INTERNATIONAL AUTOMATIC SERVICE*， 1993-01-01 Update
ITU-T E.500 Traffic Intensity Measurement Principles - Series E: Overall Network Operation Telephone Service Service Operation and Human Factors Quality of Service Network Management and Traffic Engineering - Traffic Engineering - Measurement and Recording of Traffic*， 1998-04-19 Update
ITU-T E.502 Traffic Measurement Requirements for Digital Telecommunication Exchanges Series E: Overall Network Operation Telephone Service Service Operation and Human Factors Traffic Engineering - Measurement and Recording of Traffic Study Group 2*， 2001-02-01 Update
ITU-T E.503 Traffic Measurement Data Analysis - Telephone Network and ISDN - Quality of Service@ Network Management and Traffic Engineering (Study Group II) 4 pp*， 1989-01-01 Update
ITU-T E.543 GRADES OF SERVICE IN DIGITAL INTERNATIONAL TELEPHONE EXCHANGES*， 1993-01-01 Update
ITU-T E.600 Terms and Definitions of Traffic Engineering - Telephone Network and ISDN - Quality of Service Network Management and Traffic Engineering (Study Group II) 21 pp*， 1993-01-01 Update
ITU-T Q.551 Transmission Characteristics of Digital Exchanges (Study Group 15)*， 2002-01-01 Update
ITU-T Q.552 Transmission Characteristics at 2-Wire Analogue Interfaces of Digital Exchanges Series Q: Switching and Signalling Digital Exchanges - Transmission Characteristics Study Group 15*， 2024-04-19 Update
ITU-T Q.553 Transmission Characteristics at 4-Wire Analogue Interfaces of Digital Exchanges - Series Q: Switching and Signalling Digital Exchanges - Transmission Characteristics Study Group 15*， 2024-04-19 Update
ITU-T Q.554 Transmission Characteristics at Digital Interfaces of Digital Exchanges - Series Q: Switching and Signalling Digital Exchanges - Transmission Characteristics Study Group 15; 11 pp*， 1996-04-19 Update
ITU-T Q.791 Monitoring and Measurements for Signalling System No. 7 Networks - Specifications of Signalling System No.7 Study Group XI; 20 pp; Cancelled*， 1989-01-01 Update
ITU-T Q.920 DIGITAL SUBSCRIBER SIGNALLING SYSTEM NO. 1 (DSS1) ISDN USER-NETWORK INTERFACE DATA LINK LAYER GENERAL ASPECTS*， 1993-03-01 Update
ITU-T Q.931 ISDN user-network interface layer 3 specification for basic call control Study Group 11*， 1998-05-01 Update