E.100

Definitions of terms used in international telephone operation  

E.101

Definitions of terms used for identifiers (names, numbers, addresses and other identifiers) for public telecommunication services and networks in the E-series Recommendations  

E.102

Terms and definitions for disaster relief systems, network resilience and recovery  

E.104

International telephone directory assistance service and public access  

E.105

International telephone service  

E.106

International Emergency Preference Scheme (IEPS) for disaster relief operations  

E.107

Emergency Telecommunications Service (ETS) and interconnection framework for national implementations of ETS  

E.108

Requirement for disaster relief mobile message service  

E.109

International billed number screening procedures for collect and third-party calling  

E.110

Organization of the international telephone network  

E.111

Extension of international telephone services  

E.112

Arrangements to be made for controlling the telephone services between two countries  

E.113

Validation procedures for the international telecommunications charge card service  

E.114

Supply of lists of subscribers (directories and other means)  

E.115

Computerized directory assistance  

E.116

International telecommunication charge card service  

E.117

Terminal devices used in connection with the public telephone service (other than telephones)  

E.118

The international telecommunication charge card  

E.118.1

Allocation, assignment and management of global Issuer Identifier Numbers (IINs)  

E.119

Requirements for safety confirmation and broadcast message service for disaster relief  

E.120

Instructions for users of the international telephone service  

E.121

Pictograms, symbols and icons to assist users of the telephone and telefax services  

E.122

Measures to reduce customer difficulties in the international telephone service  

E.123

Notation for national and international telephone numbers, e-mail addresses and web addresses  

E.124

Discouragement of frivolous international calling to unassigned or vacant numbers answered by recorded announcements without charge  

E.125

[Withdrawn] Inquiries among users of the international telephone service  

E.126

Harmonization of the general information pages of the telephone directories published by Administrations  

E.127

Pages in the telephone directory intended for foreign visitors  

E.128

Leaflet to be distributed to foreign visitors  

E.129

Presentation of national numbering plans  

E.130

Choice of the most useful and desirable supplementary telephone services  

E.131

Subscriber control procedures for supplementary telephone services  

E.132

Standardization of elements of control procedures for supplementary telephone services  

E.133

Operating procedures for cardphones  

E.134

Human factors aspects of public terminals: Generic operating procedures  

E.135

Human factors aspects of public telecommunication terminals for people with disabilities  

E.136

Specification of a tactile identifier for use with telecommunication cards  

E.137

User instructions for payphones  

E.138

Human factors aspects of public telephones to improve their usability for older people  

E.139

Public Internet access points  

E.140

Operator-assisted telephone service  

E.141

[Withdrawn] Instructions for operators on the operator-assisted international telephone service  

E.142

[Withdrawn] Time-to-answer by operators  

E.143

[Withdrawn] Demand operating of international circuits  

E.144

[Withdrawn] Advantages of semiautomatic international service  

E.145

[Withdrawn] Advantages of international automatic service  

E.146

[Withdrawn] Division of circuits into outgoing and incoming circuits  

E.147

[Withdrawn] Manually operated international transit traffic  

E.148

Routing of traffic by automatic transit exchanges  

E.149

Presentation of routing data  

E.150

[Withdrawn] Publication of a "list of international telephone routes"  
Deleted after ITU-T decision not to publish the list due to the impossibility of updating it in the existing international environment

E.151

Telephone conference calls  

E.152

International freephone service  

E.153

Home country direct  

E.154

International Shared Cost Service  

E.155

International Premium Rate Service  

E.156

Guidelines for ITU-T action on reported misuse of ITU-T E.164 number resources  

E.157

International calling party number delivery  

E.160

[Withdrawn] Definitions relating to national and international numbering plans  
The content of this Recommendation is now covered by ITU-T E.164 (1997)

E.161

Arrangement of digits, letters and symbols on telephones and other devices that can be used for gaining access to a telephone network  

E.161.1

Guidelines to select Emergency Number for public telecommunications networks  

E.162

[Withdrawn] Capability for seven digit analysis of international E.164 numbers at Time T  

E.163

[Withdrawn] Numbering plan for the international telephone service  
The content of this Recommendation was incorporated in ITU-T E.164 (1991)

E.164

The international public telecommunication numbering plan  
Replaces former E.163 numbering plan

E.164.1

Criteria and procedures for the reservation, assignment and reclamation of E.164 country codes and associated identification codes (ICs)  

E.164.2

ITU-T E.164 numbering resources for trials  

E.164.3

Principles, criteria and procedures for the assignment and reclamation of E.164 country codes and associated identification codes for groups of countries  

E.165

Timetable for coordinated implementation of the full capability of the numbering plan for the ISDN era (Recommendation E.164)  
This Recommendation is also published under alias number Q.11 ter

E.165.1

Use of escape code "0" within the E.164 numbering plan during the transition period to implementation of NPI mechanism  

E.166

Numbering plan interworking for the E.164 and X.121 numbering plans  
This Recommendation is published with the double number E.166 and X.122

E.167

ISDN Network Identification Codes  

E.168

[Withdrawn] Application of E.164 numbering plan for UPT  
Deleted in 2022 as a consequence of the suppression of the Universal Personal Telecommunication (UPT) service

E.168.1

[Withdrawn] Assignment procedures for universal personal telecommunications (UPT) numbers in the provisioning of the international UPT service  
Deleted in 2022 as a consequence of the suppression of the Universal Personal Telecommunication (UPT) service

E.169

Application of Recommendation E.164 numbering plan for universal international numbers for international telecommunications services using country codes for global services  

E.169.1

Application of Recommendation ITU-T E.164 numbering plan for universal international freephone numbers for international freephone service  

E.169.2

Application of Recommendation E.164 numbering plan for universal international premium rate numbers for the international premium rate service  

E.169.3

Application of Recommendation E.164 numbering plan for universal international shared cost numbers for international shared cost service  

E.170

Traffic routing  

E.171

International telephone routing plan  

E.172

ISDN routing plan  
Replaces ITU-T I.335 (1988).

E.173

Routing plan for interconnection between public land mobile networks and fixed terminal networks  

E.174

[Withdrawn] Routing principles and guidance for Universal Personal Telecommunications (UPT)  
Deleted in 2022 as a consequence of the suppression of the Universal Personal Telecommunication (UPT) service

E.175

Models for international network planning  

E.177

B-ISDN routing  

E.180

Technical characteristics of tones for the telephone service  
This Recommendation is published with the double number E.180 and Q.35

E.181

Customer recognition of foreign tones  

E.182

Application of tones and recorded announcements in telephone services  

E.183

Guiding principles for telephone announcements  

E.184

Indications to users of ISDN terminals  

E.190

Principles and responsibilities for the allocation, reservation, assignment, reclamation and management of international telecommunication numbering, naming, addressing and identification (NNAI) resources  

E.191

B-ISDN addressing  

E.191.1

Criteria and procedures for the allocation of ITU-T International Network Designator addresses  

E.193

E.164 country code expansion  

E.195

ITU-T International numbering resource administration  

E.200

[Withdrawn] Operational provisions for the maritime mobile service  
E.200 was an alias name of ITU-T F.110. Only this alias name was suppressed. ITU-T F.110 remains valid

E.201

[Withdrawn] Reference recommendation for mobile services  

E.202

Network operational principles for future public mobile systems and services  

E.210

[Withdrawn] Ship station identification for VHF/UHF and maritime mobile-satellite services  
This Recommendation is also published under alias number F.120. For more details, see F.120

E.211

[Withdrawn] Selection procedures for VHF/UHF maritime mobile services  

E.212

The international identification plan for public networks and subscriptions  

E.213

[Withdrawn] Telephone and ISDN numbering plan for land mobile stations in public land mobile networks (PLMN)  
ITU-T SG2 deleted this Recommendation on 12 August 2025 (TSB Circular 68) because it had become obsolete.

E.214

Structure of the land mobile global title for the signalling connection control part (SCCP)  

E.215

[Withdrawn] Telephone/ISDN numbering plan for the mobile-satellite services of Inmarsat  

E.216

[Withdrawn] Selection procedures for the INMARSAT mobile-satellite telephone and ISDN services  
Only the previous edition (1988) of ITU-T E.216 was published. 1993 edition was never published and the out-of-date Recommendation was definitively suppressed in 1996

E.217

Maritime communications - Ship station identity  

E.218

Management of the allocation of terrestrial trunk radio Mobile Country Codes  

E.220

Interconnection of public land mobile networks (PLMN)  

E.230

Chargeable duration of calls  

E.232

Charging for calls to subscriber's station connected either to the absent subscriber's service or to a device substituting a subscriber in his absence  
This Recommendation is also published under alias number D.104. For more details, see D.104

E.251

Old system for accounting in international telephony  
E.251 was an alias name of ITU-T D.151. Only this alias name was suppressed. ITU-T D.151 remains valid

E.252

Mode of application of the flat-rate price procedure set forth in Recommendations D.67 and D.150 for remuneration of facilities made available to the Administrations of other countries  
E.252 was an alias name of ITU-T D.160. Only this alias name was suppressed. ITU-T D.160 remains valid

E.260

Basic technical problems concerning the measurement and recording of call durations  

E.261

Devices for measuring and recording call durations  

E.270

Monthly telephone and telex accounts  
E.270 was an alias name of ITU-T D.170. Only this alias name was suppressed. ITU-T D.170 remains valid

E.275

Exchange of international traffic accounting data between Administrations using electronic data interchange (EDI) techniques  
E.275 was an alias name of ITU-T D.190. Only this alias name was suppressed. ITU-T D.190 remains valid

E.276

Transmission in encoded form of telephone reversed charge billing and accounting information  
E.276 was an alias name of ITU-T D.176. Only this alias name was suppressed. ITU-T D.176 remains valid

E.277

Conventional transmission of information necessary for the collection of charges and the accounting regarding collect and credit card calls  
E.277 was an alias name of ITU-T D.174. Only this alias name was suppressed. ITU-T D.174 remains valid

E.300

Special uses of circuits normally employed for automatic telephone traffic  

E.301

Impact of non-voice applications on the telephone network  

E.320

Speeding up the establishment and clearing of phototelegraph calls  

E.330

User control of ISDN-supported services  

E.331

Minimum user-terminal interface for a human user entering address information into an ISDN terminal  

E.350

Dynamic routing interworking  

E.351

Routing of multimedia connections across TDM-, ATM- and IP-based networks  

E.352

Routing guidelines for efficient routing methods  

E.353

Routing of calls when using international network routing addresses  

E.360.1

Framework for QoS routing and related traffic engineering methods for IP-, ATM-, and TDM-based multiservice networks  

E.360.2

QoS routing and related traffic engineering methods - Call routing and connection routing methods  

E.360.3

QoS routing and related traffic engineering methods - QoS resource management methods  

E.360.4

QoS routing and related traffic engineering methods - Routing table management methods and requirements  

E.360.5

QoS routing and related traffic engineering methods - Transport routing methods  

E.360.6

QoS routing and related traffic engineering methods - Capacity management methods  

E.360.7

QoS routing and related traffic engineering methods - Traffic engineering operational requirements  

E.361

QoS routing support for interworking of QoS service classes across routing technologies  

E.370

Service principles when public circuit-switched international telecommunication networks interwork with IP-based networks  

E.401

Statistics for the international telephone service (number of circuits in operation and volume of traffic)  

E.408

Telecommunication networks security requirements  

E.409

Incident organization and security incident handling: Guidelines for telecommunication organizations  

E.410

International network management - General information  

E.411

International network management - Operational guidance  

E.412

Network management controls  

E.412.1

Assessing the impact of resource discontinuity in transport networks on service availability  

E.413

International network management - Planning  

E.414

International network management - Organization  

E.415

International network management guidance for common channel signalling system No. 7  

E.416

Network management principles and functions for B-ISDN traffic  

E.417

Framework for the network management of IP-based networks  

E.418

Framework for network management of IMT-2000 networks  

E.419

Business oriented Key Performance Indicators for management of networks and services  

E.420

Checking the quality of the international telephone service - General considerations  

E.421

Service quality observations on a statistical basis  

E.422

Observations on international outgoing telephone calls for quality of service  

E.423

Observations on traffic set up by operators  

E.424

Test calls  

E.425

Internal automatic observations  

E.426

General guide to the percentage of effective attempts which should be observed for international telephone calls  

E.427

Collection and statistical analysis of special quality of service observation data for measurements of customer difficulties in the international automatic service  

E.428

Connection retention  

E.430

Quality of service framework  

E.431

Service quality assessment for connection set-up and release delays  

E.432

Connection quality  

E.433

Billing integrity  

E.434

Subscriber-to-subscriber measurement of the public switched telephone network  

E.436

Customer Affecting Incidents and blocking Defects Per Million  

E.437

Comparative metrics for network performance management  

E.438

Performance parameters and measurement methods to assess N-ISDN 64 kbit/s circuit-switched bearer service UDI in operation  

E.439

Test call measurement to assess N-ISDN 64 kbit/s circuit-switched bearer service UDI in operation  

E.440

Customer satisfaction point  

E.450

Facsimile quality of service on public networks - General aspects  

E.451

Facsimile call cut-off performance  

E.452

Facsimile modem speed reductions and transaction time  

E.453

Facsimile image quality as corrupted by transmission-induced scan line errors  

E.454

Transmission performance metrics based on Error Correction Mode (ECM) facsimile  

E.456

Test transaction for facsimile transmission performance  

E.457

Facsimile measurement methodologies  

E.458

Figure of merit for facsimile transmission performance  

E.459

Measurements and metrics for characterizing facsimile transmission performance using non-intrusive techniques  

E.460

Measurements and metrics for monitoring the performance of V.34 Group 3 Facsimile  

E.470

Operational considerations for QoS of voice over IP-based networks with PSTN-IP-PSTN architecture  

E.475

Guidelines for intelligent network analytics and diagnostics  

E.480

Framework for service management operational requirements - Service management  

E.490

Traffic measurement and evaluation - General survey  

E.490.1

Overview of Recommendations on traffic engineering  

E.491

Traffic measurement by destination  

E.492

Traffic reference period  

E.493

Grade of service (GOS) monitoring  

E.500

Traffic intensity measurement principles  

E.501

Estimation of traffic offered in the network  

E.502

Traffic measurement requirements for digital telecommunication exchanges  

E.503

Traffic measurement data analysis  

E.504

Traffic measurement administration  

E.505

Measurements of the performance of common channel signalling network  

E.506

Forecasting international traffic  

E.507

Models for forecasting international traffic  

E.508

Forecasting new telecommunication services  

E.510

[Withdrawn] Determination of the number of circuits in manual operation  

E.520

Number of circuits to be provided in automatic and/or semiautomatic operation, without overflow facilities  

E.521

Calculation of the number of circuits in a group carrying overflow traffic  

E.522

Number of circuits in a high-usage group  

E.523

Standard traffic profiles for international traffic streams  

E.524

Overflow approximations for non-random inputs  

E.525

Designing networks to control grade of service  

E.526

Dimensioning a circuit group with multi-slot bearer services and no overflow inputs  

E.527

Dimensioning at a circuit group with multi-slot bearer services and overflow traffic  

E.528

Dimensioning of digital circuit multiplication equipment (DCME) systems  

E.529

Network dimensioning using end-to-end GOS objectives  

E.540

Overall grade of service of the international part of an international connection  

E.541

Overall grade of service for international connections (subscriber-to-subscriber)  

E.543

Grades of service in digital international telephone exchanges  

E.550

Grade-of-service and new performance criteria under failure conditions in international telephone exchanges  

E.600

Terms and definitions of traffic engineering  

E.651

Reference connections for traffic engineering of IP access networks  

E.671

Post-selection delay in PSTN/ISDN networks using Internet telephony for a portion of the connection  

E.681

Traffic engineering methods for IP acess networks based on hybrid fiber/coax system  

E.700

Framework of the E.700-Series Recommendations  

E.701

Reference connections for traffic engineering  

E.710

[Withdrawn] ISDN traffic modelling overview  
Deleted after its content became technically out of date

E.711

User demand modelling  

E.712

User plane traffic modelling  

E.713

Control plane traffic modelling  
Only the title changes

E.716

User demand modelling in Broadband-ISDN  

E.720

ISDN grade of service concept  

E.721

Network grade of service parameters and target values for circuit-switched services in the evolving ISDN  

E.723

Grade-of-service parameters for Signalling System No. 7 networks  

E.724

GOS parameters and target GOS objectives for IN services  

E.726

Network grade of service parameters and target values for B-ISDN  

E.728

Grade-of-service parameters for B-ISDN signalling  

E.730

[Withdrawn] ISDN dimensioning methods overview  
Deleted after its content became technically out of date

E.731

Methods for dimensioning resources operating in circuit-switched mode  

E.733

Methods for dimensioning resources in Signalling System No. 7 networks  

E.734

Methods for allocating and dimensioning Intelligent Network (IN) resources  

E.735

Framework for traffic control and dimensioning in B-ISDN  

E.736

Methods for cell level traffic control in B-ISDN  

E.737

Dimensioning methods for B-ISDN  

E.743

Traffic measurements for SS No. 7 dimensioning and planning  

E.744

Traffic and congestion control requirements for SS No. 7 and IN-structured networks  

E.745

Cell level measurement requirements for the B-ISDN  

E.750

Introduction to the E.750 series of Recommendations on traffic engineering aspects of networks supporting personnal communications services  

E.751

Reference connections for traffic engineering of land mobile networks  

E.752

Reference connections for traffic engineering of maritime and aeronautical systems  

E.755

[Withdrawn] Reference connections for UPT traffic performance and GOS  
Deleted in 2022 as a consequence of the suppression of the Universal Personal Telecommunication (UPT) service

E.760

Terminal mobility traffic modelling  

E.770

Land mobile and fixed network interconnection traffic grade of service concept  

E.771

Network grade of service parameters and target values for circuit-switched public land mobile services  

E.773

Maritime and aeronautical mobile grade of service concept  

E.774

Network grade of service parameters and target values for maritime and aeronautical mobile services  

E.775

[Withdrawn] UPT grade of service concept  
Deleted in 2022 as a consequence of the suppression of the Universal Personal Telecommunication (UPT) service

E.776

[Withdrawn] Network grade of service parameters for UPT  
Deleted in 2022 as a consequence of the suppression of the Universal Personal Telecommunication (UPT) service

E.800

Definitions of terms related to quality of service  

E.801

Framework for Service Quality Agreement  

E.802

Framework and methodologies for the determination and application of QoS parameters  

E.803

Quality of service parameters for supporting service aspects  

E.804

Quality of service aspects for popular services in mobile networks  

E.804.1

Application guide for Recommendation ITU-T E.804 on quality of service aspects for popular services in mobile networks  

E.805

Strategies to establish quality regulatory frameworks  

E.805.1

Quality of service operational strategy for improved regulatory supervision of providers of mobile telecommunication services  

E.806

Measurement campaigns, monitoring systems and sampling methodologies to monitor the quality of service in mobile networks  

E.807

Definitions, associated measurement methods and guidance targets of user-centric parameters for call handling in cellular mobile voice service  

E.810

Framework of the Recommendations on the serveability performance and service integrity for telecommunication services  

E.811

Quality measurement in major events  

E.812

Crowdsourcing approach for the assessment of end-to-end quality of service in fixed and mobile broadband networks  

E.813

Mapping and visualization strategies for the assessment of connectivity  

E.820

Call models for serveability and service integrity performance  

E.830

Models for the specification, evaluation and allocation of serveability and service integrity  

E.840

Statistical framework for end-to-end network-performance benchmark scoring and ranking  

E.845

Connection accessibility objective for the international telephone service  

E.846

Accessibility for 64 kbit/s circuit-switched international end-to-end ISDN connection types  

E.847

Quality of service norms for time-division multiplexing interconnection between telecom networks  

E.850

Connection retainability objective for the international telephone service  

E.855

Connection integrity objective for the international telephone service  

E.860

Framework of a service level agreement  

E.861

Defining operations competency metrics  

E.862

Dependability planning of telecommunication networks  

E.880

Field data collection and evaluation on the performance of equipment, networks and services  

E.910

Procedures for registration within the domain ".int"  

E.1100

Specification of an international numbering resource for use in the provisioning of international help lines  

E.1110

Allocation and assignment of ITU-T E.164 country code 888  

E.1120

Assignment procedures for international telecommunication numbering, naming, addressing and identification (NNAI) resources  

E.1121

Mechanisms and processes for audits of assigned ITU-T international naming, numbering, addressing and identification (NNAI) resources  

E.4110

Framework for operations requirements of next generation networks and services  

E.100SerSup1

ITU-T E.100 series - Framework of disaster management for disaster relief system  

E.300SerSup2

[Withdrawn] Various tones used in national networks  
The information previously contained in this supplement is now available on the "International Numbering Resources" portion of ITU-T website

E.300SerSup1

List of possible supplementary telephone services which may be offered to subscribers  

E.300SerSup3

North american precise audible tone plan  

E.300SerSup4

Treatment of calls considered as terminating abnormally  

E.300SerSup5

Modelling of an experimental test design for the determination of inexperienced user difficulties in setting up international calls using nationally available instructions, or to compare different sets of instructions  

E.300SerSup6

Preparation of information to customers travelling abroad  

E.300SerSup7

Description of INMARSAT existing and planned systems  

E.800SerSup1

Table of the Erlang formula  

E.800SerSup2

Curves showing the relation between the traffic offered and the number of circuits required  

E.800SerSup5

Teletraffic implications for international switching and operational procedures resulting from a failure of a transmission facility  

E.800SerSup7

Guide for evaluating and implementing alternate routing networks  

E.Sup8

Guidelines for inter-provider quality of service  

E.800SerSup9

Guidelines on regulatory aspects of quality of service  

E.800SerSup10

ITU-T E.800 series - QoS/QoE framework for the transition from network oriented to service oriented operations  

E.Sup1

ITU-T E.1100-series - Operational aspects for the implementation of ITU-T E.164 country code 888  

E.Sup11

Criteria for M2M/IoT-related assignments under Recommendation ITU-T E.164.1 and Recommendation ITU-T E.212 Annex A