X.29
Encyclopedia
X.29 is the ITU-T
standard, approved by ISO, specifying procedures for the exchange of control information and user data between a Packet Assembler/Disassembler
(PAD), and a remote packet-mode data terminal equipment
(DTE) or another PAD. It defines the level 4 (or session layer
in the OSI model
) for X.25
communications, specifically call establishment and X.3
parameter negotiation.
Character-mode DTEs, which communicate with a PAD in a manner specified by the X.28
standard, are often referred to as X.29 terminals
.
ITU-T
The ITU Telecommunication Standardization Sector is one of the three sectors of the International Telecommunication Union ; it coordinates standards for telecommunications....
standard, approved by ISO, specifying procedures for the exchange of control information and user data between a Packet Assembler/Disassembler
Packet Assembler/Disassembler
A packet assembler/disassembler, abbreviated PAD is a communications device which provides multiple asynchronous terminal connectivity to an X.25 network or host computer. It collects data from a group of terminals and places the data into X.25 packets...
(PAD), and a remote packet-mode data terminal equipment
Data terminal equipment
Data Terminal Equipment is an end instrument that converts user information into signals or reconverts received signals. These can also be called tail circuits. A DTE device communicates with the data circuit-terminating equipment...
(DTE) or another PAD. It defines the level 4 (or session layer
Session layer
The session layer is layer 5 of the seven-layer OSI model of computer networking.The session layer provides the mechanism for opening, closing and managing a session between end-user application processes, i.e., a semi-permanent dialogue. Communication sessions consist of requests and responses...
in the OSI model
OSI model
The Open Systems Interconnection model is a product of the Open Systems Interconnection effort at the International Organization for Standardization. It is a prescription of characterizing and standardizing the functions of a communications system in terms of abstraction layers. Similar...
) for X.25
X.25
X.25 is an ITU-T standard protocol suite for packet switched wide area network communication. An X.25 WAN consists of packet-switching exchange nodes as the networking hardware, and leased lines, Plain old telephone service connections or ISDN connections as physical links...
communications, specifically call establishment and X.3
X.3
X.3 is an ITU-T standard indicating what functions are to be performed by a Packet Assembler/Disassembler when connecting character-mode data terminal equipment , such as a computer terminal, to a packet switched network such as an X.25 network, and specifying the parameters that control this...
parameter negotiation.
Character-mode DTEs, which communicate with a PAD in a manner specified by the X.28
X.28
X.28 is an ITU-T standard specifying the interface between asynchronous character-mode data terminal equipment , such as computer terminals, and a Packet Assembler/Disassembler that connects the DTE to a packet switched network such as an X.25 network.-External links:*...
standard, are often referred to as X.29 terminals
Computer terminal
A computer terminal is an electronic or electromechanical hardware device that is used for entering data into, and displaying data from, a computer or a computing system...
.