U.1

Signalling conditions to be applied in the international telex service �

U.2

Standardization of dials and dial pulse generators for the international telex service �

U.3

Arrangements in switching equipment to minimize the effects of false calling signals �

U.4

Exchange of information regarding signals destined to be used over international circuits concerned with switched teleprinter networks �

U.5

Requirements to be met by regenerative repeaters in international connections �

U.6

Prevention of fraudulent transit traffic in the fully automatic international telex service �

U.7

Numbering schemes for automatic switching networks �

U.8

Hypothetical reference connections for telex and gentex networks �

U.10

Equipment of an international telex position �

U.11

Telex and gentex signalling on intercontinental circuits used for intercontinental automatic transit traffic (type C signalling) �

U.12

Terminal and transit control signalling system for telex and similar services on international circuits (type D signalling) �

U.15

Interworking rules for international signalling systems according to Recommendations U.1, U.11 and U.12 �

U.20

Telex and gentex signalling on radio channels (synchronous 7-unit systems affording error correction by automatic repetition) �

U.21

Operator recall on a telex call set up on a radiotelegraph circuit �

U.22

Signals indicating delay in transmission on calls set up by means of synchronous systems with automatic error correction by repetition �

U.23

Use of radiotelegraph circuits with ARQ equipment for fully automatic telex calls charged on the basis of elapsed time �

U.24

Requirements for telex and gentex operation to be met by synchronous multiplex equipment described in Recommendation R.44 �

U.25

Requirements for telex and gentex operation to be met by code- and speed-dependent TDM systems conforming to Recommendation R.101 �

U.30

Signalling conditions for use in the international gentex network �

U.31

Prevention of connection to faulty stations and/or station lines in the gentex service �

U.40

Reactions by automatic terminals connected to the telex network in the event of ineffective call attempts or signalling incidents �

U.41

Changed address interception and call redirection in the telex service �

U.43

Follow-on calls �

U.44

Multi-address calls in real time for broadcast purposes in the international telex service �

U.45

Response to the not-ready condition of the telex terminal �

U.46

Interruption of automatic transmission and flow control in the international telex service �

U.60

General requirements to be met in interfacing the international telex network with maritime satellite systems �

U.61

Detailed requirements to be met in interfacing the international telex network with maritime satellite systems �

U.62

General requirements to be met in interfacing the international telex network with the fully automated maritime VHF/UHF radio system �

U.63

General requirements to be met in interfacing the international telex network with the maritime "direct printing" system �

U.70

Telex service signals for telex to teletex interworking �

U.74

Extraction of telex selection information from a calling telex answerback �

U.75

Automatic called telex answerback check �

U.80

International telex store and forward access from a telex subscriber �

U.81

International telex store-and-forward - Delivery to a telex subscriber �

U.82

[Withdrawn] International telex store and forward - Interconnection of telex store and forward units �

U.101

Signalling systems for the Intex service (types E and F signalling) �

U.102

Intex and similar services - Network requirements to effect interworking between terminals operating at different speeds �

U.140

Definitions of essential technical terms relating to telegraph switching and signalling �

U.200

The international telex service - General technical requirements for interworking �

U.201

Interworking between the teletex service and the international telex service �

U.202

Technical requirements to be met in providing the international telex service within an integrated services digital network �
This Recommendation is also included but not published in I series under alias number I.560

U.203

Technical requirements to be met when providing real-time bothway communications between terminals of the international telex service and data terminal equipments on a PSPDN or via the PSTN �

U.204

Interworking between the international telex service and the public interpersonal messaging service �

U.205

Store-and-retrieve facility for the delivery of messages from a terminal of the international telex service to a data terminal equipment which connects to a packet-switched public data network over the public switched telephone network �

U.206

Technical requirements for interworking between the international telex service and the videotex service �

U.207

Technical requirements to be met for the transfer of messages between terminals of the international telex service and Group 3 facsimile terminals connected to the PSTN �

U.208

The international telex service - Interworking with the INMARSAT C system using one-stage selection �

U.210

Intex service network requirements to effect interworking with the international telex service �

U.220

The international telex service - Technical requirements for a status enquiry function in an interworking scenario �

U.Sup1

[Withdrawn] Signalling characteristics and timing of the MARISAT telex service �

U.Sup2

[Withdrawn] Signalling arrangements in the Maritime Satellite Telex Service via the MARISAT system �

U.Sup3

[Withdrawn] Telex signalling arrangements in the Nordic Maritime Satellite coast Earth Station �