X.PC is a deprecated communications protocol developed by McDonnell-Douglas for connecting a personal computer to its Tymnet packet-switched public data telecommunications network. It is a subset of X.25, a CCITT standard for packet-switched networks. It is a full-duplex, asynchronous and error-correcting network protocol that supports up to 15 simultaneous channels. It maintains automatic error correction during any communications session between two or more computers.
X.PC was originally developed to enable connections up to 9600 baud. Unlike MNP, a competing standard proposed by Microcom, X.PC was placed in the public domain for royalty-free usage. MNP, on the other hand, initially required a $2,500 licensing fee. Microcom battled X.PC for acceptance in the marketplace, and eventually released MNP 1 through 3 into the public domain to compete. [1]
At the time, several modem manufacturers supported MNP in their products, Microcom and Racal-Vadic being major examples. Several companies announced support for X.PC, including Hayes, but none of the companies announcing support offered it in their modems. [1] X.PC quickly disappeared, and Microcom would go on to release MNP 4 and 5 into the public domain as well.
Packet radio is a digital radio communications mode used to send packets of data. Packet radio uses packet switching to transmit datagrams. This is very similar to how packets of data are transferred between nodes on the Internet. Packet radio can be used to transmit data long distances.
3Com Corporation was a digital electronics manufacturer best known for its computer network products. The company was co-founded in 1979 by Robert Metcalfe, Howard Charney and others. Metcalfe explained the name 3Com was a contraction of "Computer Communication Compatibility", with its focus on Ethernet technology that he had co-invented, which enabled the networking of computers.
X.25 is an ITU-T standard protocol suite for packet-switched data communication in wide area networks (WAN). It was originally defined by the International Telegraph and Telephone Consultative Committee in a series of drafts and finalized in a publication known as The Orange Book in 1976.
In telecommunications, packet switching is a method of grouping data that is transmitted over a digital network into packets. Packets are made of a header and a payload. Data in the header is used by networking hardware to direct the packet to its destination, where the payload is extracted and used by application software. Packet switching is the primary basis for data communications in computer networks worldwide.
Voice over Internet Protocol (VoIP), also called IP telephony, is a method and group of technologies for the delivery of voice communications and multimedia sessions over Internet Protocol (IP) networks, such as the Internet. The terms Internet telephony, broadband telephony, and broadband phone service specifically refer to the provisioning of communications services over the public Internet, rather than via the public switched telephone network (PSTN), also known as plain old telephone service (POTS).
In the IEEE 802 reference model of computer networking, the logical link control (LLC) data communication protocol layer is the upper sublayer of the data link layer of the seven-layer OSI model. The LLC sublayer acts as an interface between the media access control (MAC) sublayer and the network layer.
Loopback is the routing of electronic signals, digital data streams, or flows of items back to their source without intentional processing or modification. It is primarily a means of testing the communications infrastructure.
UUCP is an acronym of Unix-to-Unix Copy. The term generally refers to a suite of computer programs and protocols allowing remote execution of commands and transfer of files, email and netnews between computers.
GeoPort is a serial data system used on some models of the Apple Macintosh that could be externally clocked to run at a 2 Mbit/s data rate. GeoPort slightly modified the existing Mac serial port pins to allow the computer's internal DSP hardware or software to send data that, when passed to a digital-to-analog converter, emulated various devices such as modems and fax machines. GeoPort could be found on late-model 68K-based machines as well as many pre-USB Power Macintosh models. Some later Macintosh models also included an internal GeoPort via an internal connector on the Communications Slot. Apple GeoPort technology is now obsolete, and modem support is typically offered through USB.
Telebit was a US-based modem manufacturer, known for their TrailBlazer series of high-speed modems. One of the first modems to routinely exceed 9600 bit/s speeds, the TrailBlazer used a proprietary modulation scheme that proved highly resilient to interference, earning the product an almost legendary reputation for reliability despite mediocre line quality. They were particularly common in Unix installations in the 1980s and 1990s.
Hayes Microcomputer Products was a U.S.-based manufacturer of modems. The company is well known for the Smartmodem, which introduced a control language for operating the functions of the modem via the serial interface, in contrast to manual operation with front-panel switches. This smart modem approach dramatically simplified and automated operation. Today almost all modems use a variant of the Hayes command set.
Protocol spoofing is used in data communications to improve performance in situations where an existing protocol is inadequate, for example due to long delays or high error rates.
Link Access Procedure for Modems (LAPM) is part of the V.42 error correction protocol for modems.
ConnNet was a packet switched data network operated by the Southern New England Telephone Company serving the U.S. state of Connecticut.
A computer network is a group of computers that use a set of common communication protocols over digital interconnections for the purpose of sharing resources located on or provided by the network nodes. The interconnections between nodes are formed from a broad spectrum of telecommunication network technologies, based on physically wired, optical, and wireless radio-frequency methods that may be arranged in a variety of network topologies.
The Microcom Networking Protocols, almost always shortened to MNP, is a family of error-correcting protocols commonly used on early high-speed modems. Originally developed for use on Microcom's own family of modems, the protocol was later openly licensed and used by most of the modem industry, notably the "big three", Telebit, USRobotics and Hayes. MNP was later supplanted by v.42bis, which was used almost universally starting with the first v.32bis modems in the early 1990s.
Microcom, Inc. was a major modem vendor during the 1980s, although never as popular as the "big three", Hayes, U.S. Robotics (USR) and Telebit. Nevertheless, Microcom holds an important place in modem history for introducing the MNP error-correction and compression protocols, which were widely used under license by most modem manufacturers in the 1990s. The company went public in 1987. Compaq purchased publicly outstanding shares of the company in 1997.
Telenet was an American commercial packet-switched network which went into service in 1975. It was the first FCC-licensed public data network in the United States. Various commercial and government interests paid monthly fees for dedicated lines connecting their computers and local networks to this backbone network. Free public dialup access to Telenet, for those who wished to access these systems, was provided in hundreds of cities throughout the United States.
A mobile broadband modem is a type of modem that allows a personal computer or a router to receive Internet access via a mobile broadband connection instead of using telephone or cable television lines. A mobile Internet user can connect using a wireless modem to a wireless Internet Service Provider (ISP) to get Internet access.
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