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PACX
PACX (Private Automatic Computer eXchange) was a name given by Gandalf Technologies to their family of data switching products. Architecture The PACX was a centralized switch that allowed serial connections from end users to be connected to any one of a number of computers, typically mainframes. Users were equipped with small boxes with two thumbwheels on them, and by rolling the wheels to a given two-digit number they could select among the machines connected to the PACX. In typical setups, the PACX would be connected to computer terminals or modems. The switch box would be queried on connection for the user's selection, and then a direct connection would be made between the user and that machine. The system was not unlike the telephone network, and the name PACX was deliberately chosen to suggest a computer-side analog of the PABX market. Background The PACX, with its mainframe utility, was part of an era in which enterprise data services were seen to the province of an O ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PACX Panel
PACX (Private Automatic Computer eXchange) was a name given by Gandalf Technologies to their family of data switching products. Architecture The PACX was a centralized switch that allowed serial connections from end users to be connected to any one of a number of computers, typically mainframes. Users were equipped with small boxes with two thumbwheels on them, and by rolling the wheels to a given two-digit number they could select among the machines connected to the PACX. In typical setups, the PACX would be connected to computer terminals or modems. The switch box would be queried on connection for the user's selection, and then a direct connection would be made between the user and that machine. The system was not unlike the telephone network, and the name PACX was deliberately chosen to suggest a computer-side analog of the PABX market. Background The PACX, with its mainframe utility, was part of an era in which enterprise data services were seen to the province of an O ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gandalf Technologies
Gandalf Technologies, or simply Gandalf, was a Canadian data communications company based in Ottawa. It was best known for modems and terminal adapters that allowed computer terminals to connect to host computers through a single interface. Gandalf also pioneered a radio-based mobile data terminal that was popular for many years in taxi dispatch systems. The rapid rise of TCP/IP relegated many of Gandalf's products to niche status, and the company went bankrupt in 1997; its assets were acquired by Mitel. History Gandalf was founded by Desmond Cunningham and Colin Patterson in 1971, and started business from the lobby of the Skyline Hotel, which is now the Crowne Plaza Hotel, on Albert Street in Ottawa. The company's first products were industrial-looking half-bridges for remote terminals which were supported by large terminal multiplexers on the "computer end". Gandalf referred to these systems as a " PACX", in analogy to the telephony PABX which provided similar services in t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Network Switch
A network switch (also called switching hub, bridging hub, and, by the IEEE, MAC bridge) is networking hardware that connects devices on a computer network by using packet switching to receive and forward data to the destination device. A network switch is a multiport network bridge that uses MAC addresses to forward data at the data link layer (layer 2) of the OSI model. Some switches can also forward data at the network layer (layer 3) by additionally incorporating routing functionality. Such switches are commonly known as layer-3 switches or multilayer switches. Switches for Ethernet are the most common form of network switch. The first MAC Bridge was invented in 1983 by Mark Kempf, an engineer in the Networking Advanced Development group of Digital Equipment Corporation. The first 2 port Bridge product (LANBridge 100) was introduced by that company shortly after. The company subsequently produced multi-port switches for both Ethernet and FDDI such as GigaSwitch. Digital ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mainframe
A mainframe computer, informally called a mainframe or big iron, is a computer used primarily by large organizations for critical applications like bulk data processing for tasks such as censuses, industry and consumer statistics, enterprise resource planning, and large-scale transaction processing. A mainframe computer is large but not as large as a supercomputer and has more processing power than some other classes of computers, such as minicomputers, servers, workstations, and personal computers. Most large-scale computer-system architectures were established in the 1960s, but they continue to evolve. Mainframe computers are often used as servers. The term ''mainframe'' was derived from the large cabinet, called a ''main frame'', that housed the central processing unit and main memory of early computers. Later, the term ''mainframe'' was used to distinguish high-end commercial computers from less powerful machines. Design Modern mainframe design is characterized less by ra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Computer Terminal
A computer terminal is an electronic or electromechanical hardware device that can be used for entering data into, and transcribing data from, a computer or a computing system. The teletype was an example of an early-day hard-copy terminal and predated the use of a computer screen by decades. Early terminals were inexpensive devices but very slow compared to punched cards or paper tape for input, yet as the technology improved and video displays were introduced, terminals pushed these older forms of interaction from the industry. A related development was time-sharing systems, which evolved in parallel and made up for any inefficiencies in the user's typing ability with the ability to support multiple users on the same machine, each at their own terminal or terminals. The function of a terminal is typically confined to transcription and input of data; a device with significant local, programmable data-processing capability may be called a "smart terminal" or fat client. A ter ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Modem
A modulator-demodulator or modem is a computer hardware device that converts data from a digital format into a format suitable for an analog transmission medium such as telephone or radio. A modem transmits data by Modulation#Digital modulation methods, modulating one or more carrier wave signals to encode digital information, while the receiver Demodulation, demodulates the signal to recreate the original digital information. The goal is to produce a Signal (electronics), signal that can be transmitted easily and decoded reliably. Modems can be used with almost any means of transmitting analog signals, from light-emitting diodes to radio. Early modems were devices that used audible sounds suitable for transmission over traditional telephone systems and leased lines. These generally operated at 110 or 300 bits per second (bit/s), and the connection between devices was normally manual, using an attached telephone handset. By the 1970s, higher speeds of 1,200 and 2,400 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
PABX
A business telephone system is a multiline telephone system typically used in business environments, encompassing systems ranging in technology from the key telephone system (KTS) to the private branch exchange (PBX). A business telephone system differs from an installation of several telephones with multiple central office (CO) lines in that the CO lines used are directly controllable in key telephone systems from multiple telephone stations, and that such a system often provides additional features related to call handling. Business telephone systems are often broadly classified into key telephone systems, and private branch exchanges, but many hybrid systems exist. A key telephone system was originally distinguished from a private branch exchange in that it did not require an operator or attendant at the switchboard to establish connections between the central office trunks and stations, or between stations. Technologically, private branch exchanges share lineage with centra ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Office Controller
The office controller was a networking concept of the early to mid-1980s. The concept was used by PABX manufacturers as the basis of families of products in which the PBX would supply data connectivity and applications along with its traditional voice services. The office controller would be a central switch which would link users to applications and provide necessary services such as security. There was much discussion at that time of multimedia voice/data services but the conception of these services was very vague. There was no real understanding of the utility and therefore customer value of these services. As a result, office controller services were usually restricted to various forms of modem pooling. With the development of LANs and PCs, client/server became the dominant distributed application model, along with standalone applications as PCs became more powerful. As a result, the centralised model supported by the office controller fell out of style. Office controller p ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Session Initiation Protocol
The Session Initiation Protocol (SIP) is a signaling protocol used for initiating, maintaining, and terminating communication sessions that include voice, video and messaging applications. SIP is used in Internet telephony, in private IP telephone systems, as well as mobile phone calling over LTE (VoLTE). The protocol defines the specific format of messages exchanged and the sequence of communications for cooperation of the participants. SIP is a text-based protocol, incorporating many elements of the Hypertext Transfer Protocol (HTTP) and the Simple Mail Transfer Protocol (SMTP). A call established with SIP may consist of multiple media streams, but no separate streams are required for applications, such as text messaging, that exchange data as payload in the SIP message. SIP works in conjunction with several other protocols that specify and carry the session media. Most commonly, media type and parameter negotiation and media setup are performed with the Session Description ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Session Border Controller
A session border controller (SBC) is a network element deployed to protect SIP based voice over Internet Protocol (VoIP) networks. Early deployments of SBCs were focused on the borders between two service provider networks in a peering environment. This role has now expanded to include significant deployments between a service provider's access network and a backbone network to provide service to residential and/or enterprise customers. The term "session" refers to a communication between two or more parties – in the context of telephony, this would be a call. Each call consists of one or more call signaling message exchanges that control the call, and one or more call media streams which carry the call's audio, video, or other data along with information of call statistics and quality. Together, these streams make up a session. It is the job of a session border controller to exert influence over the data flows of sessions. The term "border" refers to a point of demarcation b ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Service Oriented Architecture
In software engineering, service-oriented architecture (SOA) is an architectural style that focuses on discrete services instead of a monolithic design. By consequence, it is also applied in the field of software design where services are provided to the other components by application components, through a communication protocol over a network. A service is a discrete unit of functionality that can be accessed remotely and acted upon and updated independently, such as retrieving a credit card statement online. SOA is also intended to be independent of vendors, products and technologies. Service orientation is a way of thinking in terms of services and service-based development and the outcomes of services. A service has four properties according to one of many definitions of SOA: # It logically represents a repeatable business activity with a specified outcome. # It is self-contained. # It is a black box for its consumers, meaning the consumer does not have to be aware of the se ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
