ITU-T U-Series Recommendations

(last updated: 19-Sep-1997 09:07)
 

U Series: Telegraph Switching

Telegraph Switching - General

  1. U.1 (03/93)
    Signalling conditions to be applied in the international telex service.
     
  2. U.2 (12/56)
    Standardization of dials and dial pulse generators for the international telex service.
     
  3. U.3 (12/56)
    Arrangements in switching equipment to minimize the effects of false calling signals.
     
  4. U.4 (12/72)
    Exchange of information regarding signals destined to be used over international circuits concerned with switched teleprinter networks.
     
  5. U.5 (10/76)
    Requirements to be met by regenerative repeaters in international connections.
     
  6. U.6 (06/64)
    Prevention of fraudulent transit traffic in the fully automatic international telex service.
     
  7. U.7 (03/93)
    Numbering schemes for automatic switching networks.
     
  8. U.8 (10/84)
    Hypothetical reference connections for telex and gentex networks.
     
  9. U.10 (03/93)
    Equipment of an international telex position.

Specific Signalling Schemes and Interworking Between Signalling Systems

  1. U.11 (03/93)
    Telex and gentex signalling on intercontinental circuits used for intercontinental automatic transit traffic (type C signalling).
     
  2. U.12 (03/93)
    Terminal and transit control signalling system for telex and similar services on international circuits (type D signalling).
     
  3. U.15 (03/93)
    Interworking rules for international signalling systems according to Recommendations U.1, U.11 and U.12.

Signalling Over Radio and Multiplexed Channels

  1. U.20 (12/72)
    Telex and gentex signalling on radio channels (synchronous 7-unit systems affording error correction by automatic repetition).
     
  2. U.21 (06/64)
    Operator recall on a telex call set up on a radiotelegraph circuit.
     
  3. U.22 (06/64)
    Signals indicating delay in transmission on calls set up by means of synchronous systems with automatic error correction by repetition.
     
  4. U.23 (12/72)
    Use of radiotelegraph circuits with ARQ equipment for fully automatic telex calls charged on the basis of elapsed time.
     
  5. U.24 (10/68)
    Requirements for telex and gentex operation to be met by synchronous multiplex equipment described in Recommendation R.44.
     
  6. U.25 (11/80)
    Requirements for telex and gentex operation to be met by code- and speed-dependent TDM systems conforming to Recommendation R.101.

Gentex Signalling

  1. U.30 (12/60)
    Signalling conditions for use in the international gentex network.
     
  2. U.31 (12/56)
    Prevention of connection to faulty stations and/or station lines in the gentex service.

Particular Signalling Facilities

  1. U.40 (03/93)
    Reactions by automatic terminals connected to the telex network in the event of ineffective call attempts or signalling incidents.
     
  2. U.41 (11/88)
    Changed address interception and call redirection in the telex service.
     
  3. U.43 (11/88)
    Follow-on calls.
     
  4. U.44 (11/88)
    Multi-address calls in real time for broadcast purposes in the international telex service.
     
  5. U.45 (03/93)
    Response to the not-ready condition of the telex terminal.
     
  6. U.46 (03/93)
    Interruption of automatic transmission and flow control in the international telex service.

Radiotelex Interworking

  1. U.60 (10/84)
    General requirements to be met in interfacing the international telex network with maritime satellite systems.
     
  2. U.61 (03/93)
    Detailed requirements to be met in interfacing the international telex network with maritime satellite systems.
     
  3. U.62 (03/93)
    General requirements to be met in interfacing the international telex network with the fully automated maritime VHF/UHF radio system.
     
  4. U.63 (10/84)
    General requirements to be met in interfacing the international telex network with the maritime "direct printing" system.

Interworking Between New Information Services and Telex

  1. U.70 (10/84)
    Telex service signals for telex to teletex interworking.
     
  2. U.74 (11/88)
    Extraction of telex selection information from a calling telex answerback.
     
  3. U.75 (03/93)
    Automatic called telex answerback check.

Telex Store and Forward

  1. U.80 (03/93)
    International telex store and forward access from a telex subscriber.
     
  2. U.81 (10/96)
    International telex store-and-forward - Delivery to telex.

Intex Service

  1. U.101 (03/93)
    Signalling systems for the Intex service (types E and F signalling).
     
  2. U.102 (07/96)
    Intex and similar services - Network requirements to effect interworking between terminals operating at different speeds.

Definitions

  1. U.140 (11/88)
    Definitions of essential technical terms relating to telegraph switching and signalling.

The International Telex Service

  1. U.200 (03/93)
    The international telex service - General technical requirements for interworking.
     
  2. U.201 (03/93)
    Interworking between the teletex service and the international telex service.
     
  3. U.202 (03/93) (same as I.560)
    Technical requirements to be met in providing the international telex service within an integrated services digital network.
     
  4. U.203 (03/93)
    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.
     
  5. U.204 (03/93)
    Interworking between the international telex service and the public interpersonal messaging service.
     
  6. U.205 (03/93)
    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.
     
  7. U.206 (03/93)
    Technical requirements for interworking between the international telex service and the videotex service.
     
  8. U.207 (03/93)
    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.
     
  9. U.208 (10/96)
    The international telex service - Interworking with the INMARSAT C system using one-stage selection.
     
  10. U.210 (03/93)
    Intex service Network requirements to effect interworking with the international telex service.
     
  11. U.220 (03/93)
    The international telex service - Technical requirements for a status enquiry function in an interworking scenario.