ETSI ETS 300 221 ed.1 (1993-01)

SLOVENSKI STANDARD
SIST ETS 300 221 E1:2003
01-december-2003
Terminalska oprema (TE) – Protokoli za nižje plasti skladenjskega sistema
Videotex, ki uporablja paketni dostop prek javnega komutiranega telefonskega
omrežja (PSTN)
Terminal Equipment (TE); Syntax-based videotex protocol; Lower layer protocols using
packet mode access over the Public Switched Telephone Network (PSTN)
Ta slovenski standard je istoveten z: ETSI ETS 300 221 ed.1 (1993-01)
ICS:
33.040.35 Telefonska omrežja Telephone networks
33.050.01 Telekomunikacijska Telecommunication terminal
terminalska oprema na equipment in general
splošno
SIST ETS 300 221 E1:2003 en
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

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SIST ETS 300 221 E1:2003
EUROPEAN ETS 300 221
TELECOMMUNICATION January 1993
STANDARD
Source: ETSI TC-TE Reference: DE/TE-01014
ICS: 33.020
Videotex, PSTN
Key words:
Terminal Equipment (TE);
Syntax-based Videotex lower layer protocols using packet
mode access over the Public Switched Telephone Network
(PSTN)
ETSI
European Telecommunications Standards Institute
ETSI Secretariat
F-06921 Sophia Antipolis CEDEX - FRANCE
Postal address:
650 Route des Lucioles - Sophia Antipolis - Valbonne - FRANCE
Office address:
c=fr, a=atlas, p=etsi, s=secretariat - secretariat@etsi.fr
X.400: Internet:
Tel.: +33 92 94 42 00 - Fax: +33 93 65 47 16
Copyright Notification: No part may be reproduced except as authorized by written permission. The copyright and the
foregoing restriction extend to reproduction in all media.
© European Telecommunications Standards Institute 1993. All rights reserved.
New presentation - see History box

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Whilst every care has been taken in the preparation and publication of this document, errors in content,
typographical or otherwise, may occur. If you have comments concerning its accuracy, please write to "ETSI
Standards Management Dept." at the address shown on the title page.

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Contents
Foreword .5
1 Scope .7
2 Normative references.8
3 Definitions and abbreviations .9
4 Overview .9
5 Configurations .9
6 General model.10
7 Service definition .11
7.1 Introduction .11
7.2 Kernel services .11
7.2.1 SBV_Establish.11
7.2.2 SBV_Release .11
7.3 Optional services .11
7.3.1 SBV_Channel_Open .11
7.3.2 SBV_Channel_Error.12
8 Protocol .12
9 Coding .12
10 Use of CCITT Recommendation X.3 parameters .12
11 Bearer Independent Service (BIS) for syntax-based Videotex over PSTN .12
12 Lower layers .13
12.1 Layer 3 protocols .13
12.1.1 Full-duplex mode.13
12.1.2 Half-duplex mode .13
12.1.3 Default throughput class.13
12.2 Layer 2 .13
12.2.1 Full-duplex mode.13
12.2.2 Half-duplex mode .14
12.3 Layer 1 protocol .14
13 Asynchronous interface.14
Annex A (informative): Examples of configurations .15
A.1 Symbols.15
A.2 Connection to a Videotex Host (VH) .15
A.3 Access to a Videotex Service (VS) via a Videotex Access Point (VAP) .15
A.3.1 Service selection after a dialogue with the VAP .16
A.3.2 Service selection using a VS identification .17
A.3.2.1 VS identified by a network address .17
A.3.2.2 VS identified by a name .17
A.3.2.3 Establishment of the second Virtual Call (VC) by the Videotex Terminal
(VT) .18

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A.4 Host to terminal call establishment. 18
A.5 Terminal to terminal communication . 19
Annex B (informative): Usage of supplementary services. 19
Annex C (normative): Terminal function basic state. 19
Annex D (informative): The SBV_Escape service . 19
Annex E (informative): Extended data forwarding signals. 19
Annex F (normative): BIS constraints on ISO 8208 PICS . 19
Annex G (normative): perating sequences for CCITT Recommendation V.29 short turn around . 20
G.1 Turn-ON sequence at 9 600/7 200 bits per second. 20
G.2 Turn-ON sequence at 4 800/2 400 bits per second. 21
G.3 Turn-OFF sequence . 21
G.4 Circuit 109. 21
G.5 Circuit 106. 21
History. 22

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Foreword
This European Telecommunication Standard (ETS) has been produced by the Terminal Equipment (TE)
Technical Committee of the European Telecommunications Standards Institute (ETSI).

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1 Scope
This ETS aims to meet the requirements of network operators and equipment manufacturers who are
designing equipment to operate with an increased speed on Videotex services over the Public Switched
Telephone Network (PSTN).
This ETS has a close relationship to the set of ETSs 300 072 [1] to 300 076 [5] describing the Videotex
data syntax.
This ETS specifies how to use the end-to-end protocols defined by ETS 300 223 [6] in the case of syntax-
based Videotex lower layer protocols using packet mode access over the PSTN. It also specifies how to
use the lower layers protocols defined by ETS 300 080 [7].
This ETS:
- identifies the parts of ETS 300 223 [6] which apply;
- defines the applicable protocol pillar;
- distinguishes the differences which apply to some parameters;
- distinguishes the lower layers elements which are applicable.
It is applicable to terminals supporting syntax-based Videotex lower layer protocols using packet mode
access over the PSTN to be attached to a modem. In this context, a terminal is either a Videotex Terminal
(VT), a Videotex Service Centre (VSC), a Videotex Access Point (VAP) or a Videotex Host (VH) whilst a
modem is a device providing an interface according to one of the CCITT V. series of Recommendations
contained in the Normative references of this ETS (see Clause 2).
This ETS applies only for modems using, in both directions, a synchronous interface to the attached
terminal.
For Videotex services using modems operating in "asynchronous interface", the protocols to be used are
those already defined by the national Videotex services.
In the case of syntax-based Videotex lower layer protocols using packet mode access over the PSTN, the
following principles apply when using ETS 300 223 [6]:
- the term "S/T reference point" should read "modem interface";
- the PSTN network should be used instead of the Integrated Services Digital Network (ISDN);
- in the case of syntax-based Videotex lower layer protocols using packet mode access over the
PSTN there is neither D-channel nor B-channel; the communication and signalling data are
exchanged using the protocols described in Clause 6 of this ETS;
- all parts of ETS 300 223 [6] related to the use of "ISDN supplementary services" do not apply for
syntax-based Videotex lower layer protocols using packet mode access over the PSTN";
- a communication channel is equivalent to a Virtual Circuit (VC).

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2 Normative references
This ETS incorporates by dated or undated reference, provisions from other publications. These
normative references are cited at the appropriate places in the text and the publications are listed
hereafter. For dated references, subsequent amendments to or revisions of any of these publications
apply to this ETS only when incorporated in it by amendment of revision. For undated references the latest
edition of the publication referred to applies.
[1] ETS 300 072: "Terminal Equipment (TE); Videotex presentation layer protocol,
Videotex presentation layer data syntax".
[2] ETS 300 073: "Videotex presentation layer data syntax; Geometric Display
(CEPT Recommendation T/TE 06-02, Edinburgh 1988)".
[3] ETS 300 074: "Videotex presentation layer data syntax transparent data (CEPT
Recommendation T/TE 06-03, Edinburgh 1988)".
[4] ETS 300 075: "Terminal Equipment (TE); Videotex processable data".
[5] ETS 300 076: "Terminal Equipment (TE); Videotex, Terminal Facility Identifier
(TFI)".
[6] ETS 300 223: "Integrated Services Digital Network (ISDN); Syntax-based
Videotex; Common end-to-end protocols".
[7] ETS 300 080: "Integrated Services Digital Network (ISDN); lower layer protocols
for telematic terminals".
[8] ETS 300 177: "Terminal Equipment (TE); Videotex, Photographic syntax".
[9] ETS 300 149: "Terminal Equipment (TE); Videotex, Audio syntax".
[10] CCITT Recommendation V.17 (1990): "Recommendation for a 2-wire modem
for facsimile applications with rates up to 14 400 bit/s".
[11] CCITT Recommendation V.22 bis (1988): "2400 bits per second duplex modem
using the frequency division technique standardised for use on the general
switched telephone network and on point-to-point 2-wire leased telephone-type
circuits".
[12] CCITT Recommendation V.26 bis (1988): "2400/1200 bits per second modem
standardised for use in the general switched telephone network".
[13] CCITT Recommendation V.26 ter (1988): "2400 bits per second duplex modem
using the echo cancellation technique standardised for use on the general
switched telephone network and on point-to-point 2-wire leased telephone-type
circuits".
[14] CCITT Recommendation V.27 ter (1988): "4800/2400 bits per second modem
standardised for use in the general switched telephone network".
[15] CCITT Recommendation V.29 (1988): "9600 bits per second modem
standardised for use on point-to-point 4-wire leased telephone-type circuits".
[16] CCITT Recommendation V.32 (1988): "A family of 2-wire, duplex modems
operating at data signalling rates of up to 9600 bit/s for use on the general
switched telephone network and on leased telephone-type circuits".
[17] CCITT Recommendation V.33 (1988): "14 400 bits per second modem
standardised for use on point-to-point 4-wire leased telephone-type circuits".

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[18] CCITT Recommendation V.42 (1988): "Error correcting procedures for DCEs
using asynchronous-to-synchronous conversion".
[19] CCITT Recommendation X.3 (1992): "Packet assembly disassembly facility
(PAD) in a public data network".
[20] CCITT Recommendation X.32 (1988): "Interface between Data Terminal
Equipment (DTE) and Data-Circuit-Terminating Equipment (DCE) for terminals
operating in the packet mode and accessing a packet switched public data
network through a public switched telephone network or an integrated service
digital network or a circuit switched public data network".
[21] CCITT Recommendation X.75 (1988): "Packet-switched signalling system
between public networks providing data transmission services".
[22] ISO 8208 (1990): "Information processing systems - Data communications -
X.25 packet level protocol for data terminal equipment".
[23] CCITT Recommendation T.71 (1988): "Link access protocol balanced (LAPB)
extended for half-duplex physical level facility".
[24] ISO 7776: "Information processing systems - Data communications -
Description of the X.25 LAPB - compatible DTE data link procedures".
3 Definitions and abbreviations
The definitions and abbreviations of ETS 300 223 [6] apply. Those related to ISDN are not used in this
ETS. In addition, the following definition applies:
Modem: an equipment which supplies the signals conversion in order to allow data transmission on the
PSTN.
4 Overview
Clause 4 of ETS 300 223 [6] applies with the exception of subclause 4.5
5 Configurations
Various configurations and topologies may be used, examples of which are given in Annex A
(informative). It shall be the responsibility of the Videotex service providers to opt for the appropriate
configuration(s) in the definition of the syntax-based Videotex lower layer protocols using packet mode
access over the PSTN service.

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6 General model
Clause 6 of ETS 300 233 [6] applies with the following exceptions:
- the Access Network shall be the PSTN (see figure 1 below);
- there is no "Co-ordination Function" for syntax-based Videotex lower layer protocols using packet
mode access over the PSTN (see NOTE 1 and figure 2 of subclause 6.2 of ETS 300 223 [6]).
Terminal
Access
Function
Function
7 7
Access Network
3 3
2 2
1 1
PSTN
Figure 1: Access Network scenario
In addition, the following figure describes the protocol pillar which shall be used:
7 ETS 300 223 [6], this ETS,
ETS 300 072 [1] to ETS 300 076 [5],
ETS 300 177 [8], ETS 300149 [9]
6 Null (NOTE)
5 Null
4 Null
3 ISO 8208 [22]
2 X.32 [21], (LAPX) X.75 [21]
ISO 7776 [24]
NOTE
...