SIST ETS 300 835 E1:2003

Multimedia Terminals and Applications (MTA); Programmable Communication Interface (PCI) for file transfer over Integrated Services Digital Network (ISDN)

1. Service definition for 2 protocol stacks ETS 300 075 & EN 41216 (ISP10607)  Simple FTAM . 2. Contribution for the extension of existing APIs for use by  simple FT esp re current wk on APPLI/COM. & XFTAM, XOPEN.

Multimedijski terminali in aplikacije (MTA) – Programirljivi komunikacijski vmesnik (PCI) za prenos datotek prek digitalnega omrežja z integriranimi storitvami (ISDN)

General Information

• Status: Published
• Publication Date: 30-Nov-2003
• ICS: 33.080 - Integrated Services Digital Network (ISDN)
• ICS: 35.180 - IT Terminal and other peripheral equipment
• Technical Committee: SS EIT - Technical Board for the electrotechnical, information technology and telecommunications fields
• Current Stage: 6060 - National Implementation/Publication (Adopted Project)
• Start Date: 01-Dec-2003
• Due Date: 01-Dec-2003
• Completion Date: 01-Dec-2003
• Mandate: T-301
• Ref Project: ETSI ETS 300 835 ed.1 (1998-09) - Multimedia Terminals and Applications (MTA); Programmable Communication Interface (PCI) for file transfer over Integrated Services Digital Network (ISDN)

Standards Content (Sample)

SLOVENSKI STANDARD
01-december-2003
Multimedijski terminali in aplikacije (MTA) – Programirljivi komunikacijski vmesnik
(PCI) za prenos datotek prek digitalnega omrežja z integriranimi storitvami (ISDN)
Multimedia Terminals and Applications (MTA); Programmable Communication Interface
(PCI) for file transfer over Integrated Services Digital Network (ISDN)
Ta slovenski standard je istoveten z: ETS 300 835 Edition 1
ICS:
33.080 Digitalno omrežje z Integrated Services Digital
integriranimi storitvami Network (ISDN)
(ISDN)
35.180 Terminalska in druga IT Terminal and other
periferna oprema IT peripheral equipment
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

EUROPEAN ETS 300 835
TELECOMMUNICATION September 1998
STANDARD
Source: MTA Reference: DE/MTA-001043
ICS: 33.020
Key words: API, FT, ISDN, PCI, terminal
Multimedia Terminals and Applications (MTA);
Programmable Communication Interface (PCI) for file transfer
over Integrated Services Digital Network (ISDN)
ETSI
European Telecommunications Standards Institute
ETSI Secretariat
Postal address: F-06921 Sophia Antipolis CEDEX - FRANCE
Office address: 650 Route des Lucioles - Sophia Antipolis - Valbonne - FRANCE
Internet: [e-mail] - http://www.etsi.fr - http://www.etsi.org
Tel.: [phone] - Fax: [phone]
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 1998. All rights reserved.

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ETS 300 835: September 1998
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 Making Support Dept." at the address shown on the title page.

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ETS 300 835: September 1998
Contents
Foreword .7
1 Scope .9
2 Normative references.9
3 Definitions and abbreviations .10
3.1 Definitions .10
3.2 Abbreviations .10
4 Overview .11
5 General principles .11
5.1 General model .12
5.2 Field of application.14
5.3 Exchange of information.14
5.4 PCI services.15
5.5 Service profiles .15
6 Functional behaviour .16
6.1 PCI mechanism .16
6.1.1 Monitoring.16
6.1.2 Alarm handling .16
6.1.3 LA selection mechanism .16
6.1.4 Redirection of incoming calls.17
6.2 Description of PCI identifier .17
6.2.1 Connection identifier.17
6.2.2 CA identifier.17
6.2.3 Network connection identifier .17
6.2.4 File transfer service identifier .18
6.2.5 File transfer connection identifier .18
6.3 Sequences using the PCI .18
6.3.1 Login to a CA.18
6.3.2 Sending and receiving IDUs.18
6.3.3 Monitoring.21
6.3.4 Receiving a file .21
6.3.5 Logout .22
6.4 Transitions at the PCI .22
6.4.1 Idle state.23
6.4.2 Logged state.23
6.4.3 Network connected state.23
6.4.4 File Transfer connected state.23
6.5 Error Handling.23
6.5.1 PCI errors.23
6.5.2 Protocol error codes.23
6.5.3 Network error codes.24
7 Exchange mechanism.24
7.1 Overview of interactive exchange mechanism functions.24
7.2 General PCI parameters.25
7.2.1 Alarm support.25
7.2.2 Monitor support .25
7.3 Interactive exchange mechanism functions.25
7.3.1 Function IA_Login .25
7.3.1.1 Purpose .26
7.3.1.2 Behaviour.26
7.3.1.3 Parameters .27

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ETS 300 835: September 1998
7.3.2 Function IA_Logout. 27
7.3.2.1 Purpose. 27
7.3.2.2 Behaviour. 27
7.3.2.3 Parameters . 27
7.3.3 Function IA_Send . 27
7.3.3.1 Purpose. 28
7.3.3.2 Behaviour. 28
7.3.3.3 Parameters . 28
7.3.4 Function IA_Monitor. 28
7.3.4.1 Purpose. 28
7.3.4.2 Behaviour. 29
7.3.4.3 Parameters . 29
7.3.5 Function IA_Alarm . 30
7.3.5.1 Purpose. 30
7.3.5.2 Behaviour. 31
7.3.5.3 Parameters . 31
8 Interface Data Units (IDUs) . 31
8.1 Network connection services . 33
8.1.1 Establishment of a network connection . 33
8.1.2 Release a network connection. 33
8.1.3 Send transparent data . 34
8.2 File transfer connection services. 34
8.2.1 One step procedure. 35
8.2.1.1 Establishment of a file transfer connection . 35
8.2.1.2 Termination of a file transfer connection. 35
8.2.2 Two step procedure. 35
8.2.2.1 Establishment of a file transfer association . 35
8.2.2.2 Establishment of a file access. 36
8.2.2.3 Release of a file access. 36
8.2.2.4 Termination of a file transfer association . 36
8.2.3 Abort of a file transfer connection. 36
8.3 File transfer services . 37
8.3.1 Send file. 37
8.3.2 Send message. 38
8.3.3 Receive file . 38
8.3.4 Delete file. 38
8.3.5 Rename file. 38
8.3.6 Cancel a file operation . 39
8.3.7 End of a file operation. 39
8.3.8 Read file attributes. 39
8.3.9 Change file attributes. 39
8.3.10 List remote filestore information . 40
8.3.11 Navigation on the remote filestore. 40
8.4 Local PCI services. 40
8.4.1 Redirection of incoming calls. 40
8.4.2 List connected LAs . 41
8.4.3 List local filestore information . 41
9.4.4 Read CA capabilities . 41
8.4.5 Read CA configuration. 41
8.4.6 Read phonebook entry . 42
8.4.7 Read logbook. 42
8.4.8 Read access control information . 42
9 Service definition . 42
9.1 General IDU parameters. 43
9.2 SimpleFTAM service definition. 44
9.2.1 SimpleFTAM IDUs. 45
9.2.2 SimpleFTAM specific IDU parameters . 45
9.2.3 Network connection services. 54
9.2.3.1 Establishment of a network connection . 55
9.2.3.2 Release of a network connection. 55
9.2.4 File transfer connection services . 56

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ETS 300 835: September 1998
9.2.4.1 Establishment of a file transfer connection.56
9.2.4.2 Termination of a file transfer connection .58
9.2.4.3 Abort of a file transfer connection.59
9.2.5 File transfer services .59
9.2.5.1 Send file.59
9.2.5.2 Receive file .61
9.2.5.3 Delete file.62
9.2.5.4 Rename file .63
9.2.5.5 Cancel file operation.64
9.2.5.6 End of file operation.64
9.2.5.7 Read file attributes.65
9.2.5.8 Change file attributes.66
9.2.5.9 List remote filestore information .66
9.2.5.10 Navigation on the remote filestore.68
9.2.6 Local PCI services.69
9.2.6.1 Redirection of incoming calls.69
9.2.6.2 List connected LAs .69
9.2.6.3 List local filestore information .70
9.2.6.4 Read CA capability .70
9.2.6.5 Read CA configuration.70
9.2.6.6 Read phonebook entry .71
9.2.6.7 Read logbook.71
9.2.6.8 Read access control information .72
9.2.7 SimpleFTAM profile specification.72
9.3 Easyfile Service definition .82
9.3.1 Easyfile IDUs.83
9.3.2 Easyfile specific IDU parameters .83
9.3.3 Network connection services.87
9.3.3.1 Establishment of a network connection.87
9.3.3.2 Release of a network connection .88
9.3.3.3 Transparent data .88
9.3.4 File transfer connection services.89
9.3.4.1 One step procedure.89
9.3.4.1.1 Establishment of a file transfer
connection.89
9.3.4.1.2 Termination of a file transfer
connection.89
9.3.4.2 Two steps procedure .90
9.3.4.2.1 Establishment of a file transfer
association.90
9.3.4.2.2 Establish file transfer access .91
9.3.4.2.3 Release file transfer access.92
9.3.4.2.4 Termination of a file transfer
association.92
9.3.4.3 Abort a file transfer connection.92
9.3.5 File transfer services .93
9.3.5.1 Send file.93
9.3.5.2 Message .94
9.3.5.3 Receive file .94
9.3.5.4 Delete file.96
9.3.5.5 Rename file .96
9.3.5.6 Cancel file operation.97
9.3.5.7 End of file operation.97
9.3.5.8 List remote filestore information .98
9.3.5.9 Navigation on the remote filestore.98
9.3.6 Local PCI services.99
9.3.6.1 Redirection of incoming calls.99
9.3.6.2 List connected LAs .99
9.3.6.3 List local filestore information .100
9.3.6.4 Read CA capabilities .100
9.3.6.5 Read CA configuration.100
9.3.6.6 Read phonebook entry .101
9.3.6.7 Read logbook.101

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ETS 300 835: September 1998
9.3.6.8 Read access control information. 102
9.3.7 Easyfile profile specification. 102
10 CA capability description. 108
11 Binary encoding scheme . 109
11.1 General types definition. 109
11.2 IDU encoding scheme. 110
11.3 SimpleFTAM specific encoding scheme . 111
11.3.1 General constants and type definitions. 111
11.3.2 SimpleFTAM IDUs. 112
11.3.2.1 SimpleFTAM IDU values. 118
11.4 Easyfile specific encoding scheme . 121
11.4.1 EasyfileIDU parameters. 127
11.4.2 EasyfileIDU values. 127
12 Platform dependencies. 128
12.1 Implementation dependencies . 128
12.2 General types and definitions. 128
12.3 Windows C function prototypes and definitions . 129
12.3.1 IA_Login function . 129
12.3.2 IA_Monitor function. 129
12.3.3 IA_Alarm function . 130
12.3.4 IA_Logout function. 130
12.3.5 IA_Send function . 130
12.4 UNIX. 131
12.5 OS/2 . 131
12.6 MacOS . 131
Annex A (normative): Error codes . 132
Annex B (informative): File Transfer Protocol (FTP) service definition . 133
B.1 FTP IDUs. 133
B.2 FTP specific IDU parameters . 133
B.3 Network connection services. 134
B.3.1 Establishment of a network connection. 134
B.3.2 Release of a network connection . 134
B.4 File transfer connection services . 135
B.4.1 Establishment of a file transfer connection . 135
B.4.2 Termination of a file transfer connection. 135
B.4.3 Abort a file transfer connection . 135
B.5 File transfer services . 136
B.5.1 Send File . 136
B.5.2 Receive File. 136
B.5.3 Delete File . 137
B.5.4 Rename file . 137
B.5.5 Cancel File Operation. 137
B.5.6 End of File Operation . 138
B.5.7 List remote filestore information. 138
B.5.8 Navigation on the remote filestore . 139
Annex C (informative): Examples of information exchange . 140
History. 143

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ETS 300 835: September 1998
Foreword
This European Telecommunication Standard (ETS) has been produced by the Multimedia Terminals and
Applications (MTA) Project of the European Telecommunications Standards Institute (ETSI).
Transposition dates
Date of adoption of this ETS: 18 September 1998
Date of latest announcement of this ETS (doa): 31 December 1998
Date of latest publication of new National Standard
or endorsement of this ETS (dop/e): 30 June 1999
Date of withdrawal of any conflicting National Standard (dow): 30 June 1999

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ETS 300 835: September 1998
1 Scope
This European Telecommunication Standard (ETS) specifies the Programmable Communication Interface
(PCI) for interactive services, i.e. for file transfer services over Integrated Services Digital Network (ISDN).
In particular it defines the access to and administration of the file transfer services:
- File Transfer, Access and Management (FTAM) simple file transfer as defined in ETS 300 388 [5];
- Eurofile transfer as defined in ETS 300 383 [4].
The simple file transfer teleservice over ISDN was specified in ETS 300 388 [5] in conformance with the
international standard FTAM (ISO/IEC 8571, parts 1 to 5 [9]) and the ISO/IEC profile specification
AFT11 (see ISO/IEC 10607-3 [10]). The FTAM simple file transfer over ISDN is a subset of FTAM (File
Transfer, Access and Management) and is called SimpleFTAM in the present document.
Eurofile is an ISDN teleservice specified in ETS 300 383 [4], in which end-to-end compatibility between
terminals is guaranteed and which supports file exchanges between different types of equipment. This
teleservice is also called Easyfile.
This ETS completes the work related to the need for a standardized simple file transfer protocol over
ISDN by fulfilling the part 3 of the overall project. The outcome of part 1 of this overall project was
ETR 074 [8], the outcome of part 2 was ETS 300 383 [4] and ETS 300 388 [5]. This ETS is therefore
based upon the documents ETR 074 [8], ETS 300 383 [4] and ETS 300 388 [5].
Additionally the PCI of this ETS was specified according to the philosophy, the general principles and rules
of the APPLI/COM interface. APPLI/COM is a PCI which was designed to unify the access and the
administration of facsimile group 3, facsimile group 4, teletex, telex, e-mail and file transfer in the master-
slave relationship. This ETS establishes therefore an extension of ETS 300 243-1 [3], the APPLI/COM
specification, for interactive services, i.e. for file transfer services, defining:
- the services offered at the PCI;
- the information exchanged at the PCI;
- the method how the information are exchanged at the PCI.
The exchange method of this ETS shall be a general mechanism applicable to different types of
interactive services. Therefore this ETS shall be used as a framework for future recommendations which
addresses other file transfer protocols or interactive services and other networks than ISDN.
2 Normative references
This ETS incorporates by dated and 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 or revision. For undated references the latest
edition of the publication referred to applies.
[1] ETS 300 075: "Terminal Equipment (TE); Processable data, File transfer".
[2] ETS 300 079 (1991): "Integrated Services Digital Network (ISDN); Syntax-based
videotex End-to-end protocols, circuit mode DTE-DTE".
[3] ETS 300 243-1 (1995): "Terminal Equipment (TE); Programmable
Communication Interface (PCI) APPLI/COM for facsimile group 3, facsimile
group 4, teletex and telex services; Part 1: CCITT Recommendation T.611
(1992) [modified]".
[4] ETS 300 383 (1995): "Integrated Services Digital Network (ISDN); File transfer
over the ISDN EUROFILE transfer profile".
[5] ETS 300 388 (1995): "Integrated Services Digital Network (ISDN); File Transfer
Access Management (FTAM) over ISDN based on simple file transfer profile".

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ETS 300 835: September 1998
[6] ETS 300 409 (1995): "Integrated Services Digital Network (ISDN); Eurofile
transfer teleservice; Service description".
[7] ETS 300 410 (1995): "Integrated Service Digital Network (ISDN): File Transfer &
Access Management (FTAM) teleservice; Service description".
[8] ETR 074 (1993): "Terminal Equipment (TE); File transfer over the Integrated
Services Digital Network (ISDN)".
[9] ISO/IEC 8571 (1988): "Information processing systems - Open Systems
Interconnection - File Transfer, Access and Management:
Part 1: General introduction;
Part 2: Virtual Filestore Definition;
Part 3: File Service Definition;
Part 4: File Protocol Specification;
Part 5: Protocol Implementation Conformance Statement Proforma (1990)".
[10] ISO/IEC 10607-3 (1995): "Information technology - International Standardized
Profiles AFTnn - File Transfer, Access and Management; Part 3: AFT11 -
Simple File Transfer Service (unstructured)".
[11] ITU-T Recommendation Q.931: "Digital Subscriber Signalling System No 1
(DSS 1); ISDN user-network interface layer 3 specification for basic call control".
3 Definitions and abbreviations
3.1 Definitions
For the purposes of this ETS, the following definitions apply:
m: Any feature denoted by "m" (mandatory) shall be supported by all implementations claiming
conformance to this ETS.
o: Any feature denoted by "o" (optional) is left to the implementations claiming conformance to this
ETS whether this feature is implemented or not.
c: Any feature denoted by "c" (conditional) shall be supported under the conditions specified in this
ETS by all implementations claiming conformance to this ETS.
x: Any feature denoted by "x" (excluded) shall not be implemented by all implementations claiming
conformance to this ETS.
i: Any feature denoted by "i" (outside the scope) is outside the scope of this ETS.
-: Any feature denoted by "-" (not applicable) is not applicable for the context of this ETS.
3.2 Abbreviations
For the purposes of this ETS, the following abbreviations apply:
ASE Application Service Element
CA Communication Application
DLL Dynamic Link Library
FADU File Access Data Unit
FTAM File Transfer, Access and Management
FTP File Transfer Protocol
FU Functional Unit
ICE Interface Configuration Environment
IDU Interface Data Unit
ISDN Integrated Service Digital Network
LA Local Application
LAN Local Area Network
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ETS 300 835: September 1998
MSN Multiple Subscriber Number
NBS National Bureau of Standards
NSAP Network Service Access Point
PCI Programmable Communication Interface
RIC Redirection of Incoming Calls
UA User Agent
VFS Virtual File Store (FTAM)
4 Overview
The interface specified in this ETS is designed for interactive communications services, i.e. for the file
transfer services SimpleFTAM and Easyfile.
The general model, the general principles and aspects which have guided the specification of the
Programmable Communication Interface (PCI) for file transfer over ISDN are described in clause 5.
Clause 6 contains a description of the flow of information at the interface specified in this ETS.
The functions which shall be used to exchange information at the interface, the parameters which shall be
used independently from the file transfer service at the interface and principles which shall be used to
handle and manage the exchange of information at the interface are specified in clause 7.
The service primitives used to exchange information at the interface are defined in clause 8.
The meaning, the structure and the data types of the Interface Data Units are defined in clause 9. This
clause contains:
- the specification of general, service independent parameters of each Interface Data Unit (IDU);
- the SimpleFTAM service definition comprising the Interface Data Units (IDUs) and their parameters
as applicable for SimpleFTAM;
- the Easyfile service definition comprising the Interface Data Units (IDUs) and their parameters as
applicable for Easyfile.
The interface of this ETS was specified independently from programming languages, hardware platforms
and operating systems. Implementors who wants to develop a product according to this ETS will face
parts which are product specific and which depend on the real computing environment. The decisions how
to realize such parts are left to the product developers. To guarantee that the components of a
communications system are capable of communicating with each other, those product specific features
and services shall be provided by the manufacturer of a product as described in clause 10.
The binary encoding scheme of the IDUs are specified in clause 11 using the programming language C as a
formal description language.
Clause 12 contains the most important platform dependencies to assist implementors to develop their
product according to this ETS.
Annex A contains the description of error codes.
Two informative annexes are provided in this ETS:
- Annex B: File Transfer Protocol (FTP) service definition. The file transfer service FTP is a widely
spread and accepted standard. Annex A shows how to use the FTP service at the PCI of this ETS.
- Annex C: Examples of information exchange. This annex illustrates the exchange of information at
the PCI using concrete examples.
5 General principles
The general model, the general principles and aspects which have guided the specification of the PCI of
this ETS are defined in the following subclauses.

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5.1 General model
The interface specified in this ETS was designed to be independent from:
- operating systems;
- hardware platforms;
- programming languages.
The interface of this ETS is a Programmable Communication Interface (PCI) in an open communications
system. Such a communications system comprises a set of components which are located either on the
same physical medium (one computer) or on distributed physical media (more than one computer
connected via e.g. an LAN). The basic components of a communications system addressed in this ETS
are:
- Communication Application (CA): the CA is the component of a communications system which
provides communications services;
- Local Application (LA): the LA is the component of a communications system which uses the
communications services offered by the CA.
Different products as a realization of the CA may offer their services in many different ways. This PCI was
specified to abstract from such individual properties, to unify the access and performance of the services
offered by the CA, and to make LA and CA independent from each other.
The following figure illustrates in a simplified way the main components of a communications system
addressed in this ETS.
Local Application
(LA)
PCI
Communication Application
(CA)
Figure 1: Simplified general model
The relationship between LA and CA as presented in figure 1 is called one-to-one relationship
(1:1 relationship). This simple relationship between LA and CA does not cover the need of
communications systems as they are commonly used and widely spread today. Different LAs may want to
use the services of a CA at the same time. Furthermore, an LA may want to access the services of
different CAs over the same PCI simultaneously.
Therefore, the LA-CA relationships which shall be supported at the PCI of this ETS are:
- one-to-one relationship (1:1 relationship): one LA uses the offered services of one CA exclusively;
- many-to-one relationship (m:1 relationship): more than one LA use the offered services of one CA
at the same time;
- one-to-many relationship (1:n relationship): one LA uses the services of different CAs at the same
time;
- many-to-many relationship (m:n relationship): more than one LA use the services of different CAs at
the same time.
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ETS 300 835: September 1998
The many-to-many relationship is the superset of the possible LA-CA relationships in a communications
system which shall be supported by implementations claiming to be conformant to this ETS. The following
picture shows an example of the many-to-many relationship.
LA-1 LA-2 LA-3 LA-4
PCI
CA-1 CA-2
Figure 2: m:n relationships
The communications system in this example consists of four LAs (LA-1, LA-2, LA-3, LA-4) and two CAs
(CA-1, CA-2) communicating with each other through the same PCI.
LA-1 and LA-3 communicate with CA-1 and CA-2. That means that both LAs have established one local
communications channel with CA-1 and one local communications channel with CA-2 to access the
services offered by CA-1 and CA-2. LA-1 and LA-3 shall be able to handle these local communication
channels and the flow of information exchanged. LA-2 has established one communications channel with
CA-1, whereas LA-4 has established two communications channels with CA-2 to access the services
offered by CA-2.
CA-1 shall be able to handle the local communications channels with LA-1, LA-2 and LA-3 and to offer its
services to the three LAs through the PCI at the same time. In addition, CA-2 shall be able to handle the
local communications channels with LA-1, LA-3 and LA-4, and to offer its services to the three LAs
through the PCI at the same time.
A communications system designed according to this ETS provides benefits for both LAs and CAs:
- interoperability:
components which are developed by different manufacturers and which are conformant with this
ETS work well together if they are used in the same communications system;
- compatibility:
components which offer the same service(s) and which are developed in conformance with this
ETS are compatible in their behaviour; they can be exchanged with each other without affecting the
other components of the system;
- extensibility:
a system built according to this ETS is easily extendible:
- new CA(s) may be incorporated in an existing communications system which offer the same
or different communications service(s) and/or access to the same or different
communications network(s) through the PCI;
- an existing system may be extended by new applications (i.e. new LAs) using the service(s)
offered at the PCI;
- ease of use and understandability:
from the viewpoint of an LA, the PCI of this ETS simplifies the access to the communications
service(s) and network(s); this means that no exhaustive knowledge of the corresponding
communications protocols is necessary.

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ETS 300 835: September 1998
5.2 Field of application
The PCI of this ETS is an application layer oriented interface, designed for interactive communications
services.
The interactive services addressed in this ETS are the file transfer services SimpleFTAM and Easyfile.
Therefore, a CA which claims to be conformant with this ETS shall provide:
- access to at least one of the file transfer services specified in this ETS;
- access to physical ISDN;
- the many-to-many relationship between the LAs and CAs.
Other interactive services (e.g. voice communications services) may be specified following the philosophy,
the general model, the general rules and concepts of this ETS. This means in particular that all those
clauses (i.e. clause 9 and clause 11) which deal with file transfer services exclusively shall be adapted or
extended with the requirements of the communications protocols of such interactive services.
5.3 Exchange of information
The information exchanged at the PCI is structured information composed of a set of parameters. These
parameters are either service independent or service dependent.
Service independent parameters are used locally at the PCI to manage the flow of information between
LA(s) and CA(s). They have no influence on the services requested at the PCI and the communication
with a remote system. These parameters shall be used for all services offered at the PCI. They are called
general PCI parameters. The general PCI parameters are specified in clause 7 of this ETS.
Service dependent parameters are those parameters which carry service specific information. The
collection of those parameters necessary to request one service at the PCI are called Interface Data Units
(IDU). The parameters of the IDUs are divided into:
- general IDU parameters are used to handle and control the IDUs exchanged between LA(s) and
CA(s) at the PCI; consequently these parameters shall be used for each service requested with an
IDU; the general IDU parameters are specified in subclause 9.1;
- service specific IDU parameters are used to interchange data necessary to perform the requested
interactive communications service; consequently these parameters are dependent from the
services which are supported by a CA.
The general structure of the information exchanged at the PCI of this ETS are presented in the figure 3.
parameters
general PCI parameters IDU
service specific
general IDU
IDU parameters
parameters
Figure 3: General structure of the exchanged information
...