x2

Reading: X two
Field:
Communication service > public network > telephone line/modem > x2

Standard of analog modem of the highest transmission speed 56kbps which the US Robotics corporation (presently 3Com corporation absorption) developed. Central telephone exchange -> speed of member house direction (to be plugged when downloading) appears to 56kbps, but opposite direction (when uploading) appears to only 33.6kbps. You disputed extremely, centering on the K56flex standard and standard of the Rockwell corporation which does not have compatibility with the same efficiency, but 56k mode m standard was unified in 1998 February as V.90 system with ITU.

X.200

Reading: In x [hi] [ya] [ku]
Field:
Network technology > OSI reference model > X.200

At one of the advice of ITU-TS (International Telecommunication Union telecommunications standardization sector), those which stipulate the OSI reference model. With ISO (International Organization for Standardization) it is standardized as ISO 7498.

As for OSI (Open Systems Interconnection) with design policy of network structure because data communication between the strange type is actualized, the OSI reference model (OSI basic reference model) is the model which divides the function which the communication equipment should have on the basis of this policy into layered structure.

With X.200 we have defined the class to of 7th layer (application layer) from 1st layer (physical layer), the OSI service which corresponds in the X.210 series, the OSI protocol which corresponds in the X.220 series is advised respectively. … The continuation is read

The model which is defined with X.200 is utilized although communication service and protocol are designed, well, but almost there was no thing where the OSI series which is defined in the X.210 series and the X.220 series as a concrete service and a protocol is used.

X.25

Reading: X rainbow [yu] [u]
Field:
Communication service > public network > X.25

ITU-TS (the International Telecommunication Union telecommunications standardization sector) at one of advice, protocol in order to do packet transmission via the public network.

As for X.25 DCE (Data Circuit-terminating Equipment: Circuit terminating set) with DTE (Data Terminal Equipment: The terminal unit) being something which decides the interface between, it decides the specification which extends over physical layer, data link layer and the network layer in the OSI reference model. PLP which is protocol of network layer (Packet Level Protocol) there are also times when thing is called especially X.25 protocol. Thing of the packed switching network which does communication with X.25 is called X.25 network.

X.400 series

Reading: The x it is the [hi] [ya] [ku] series can body
Field:
Internet > mail > X.400 series

At one of the advice of ITU-TS (International Telecommunication Union telecommunications standardization sector), those which define the specification because the E-mail system is actualized. It consists the advice 30 of the X.400 turn stands.

The E-mail system which is defined with X.400 is called “MHS”, (Message Handling System) consists protocol of application layer (7th layer) of the OSI reference model. 1984, CCITT which is the predecessor of present ITU advised first version, “MOTIS” of the E-mail standard due to ISO (International Organization for Standardization) in revised edition 1988 (Message-Oriented Text Interchange Systems) specification was standardized.

MHS is formed MTA (Message Transfer Agent) which does message transmission, MS (Message Store) and with UA (User Agent which retains the message which is received) and the like which the user operates, the case where the respective function and it operates and communicates protocol etc are decided. … The continuation is read

As for MHS as a E-mail system as for spreading widely it was not, the TCP/IP based system which combines SMTP and POP etc attendant upon the spread of Internet spread. Those which are called present E-mail when there are no especially notes, point to this. As for MHS there is an example and the like which is adopted as the message switching system of the H procedure which is one of the Japanese EDI standard.

X.500 series advice <X.500 series recommendations>

Reading: X [hi] [ya] [ku] series can body
Field:
LAN > Computer system > X.500 series advice

ITU-T decided, the standard regarding the dispersion directory service with respect to network. Be able to construct the name space which was standardized in the entire world, it can search the data and the like easily. The communication protocol which the X.500 series is stipulated is called DAP (Directory Access Protocol) with. On Internet, it is something which LDAP which is used well with respect to TCP/IP network that tries hits to the subset of DAP, can utilize the function of the X.500 series by relatively light load. X.500 series advice is the standard whose, application such as the field which does the distributed management of the data is easy, the various X.500 corresponding software are developed.