Cable telephony

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Cable telephony is a form of digital telephony over cable TV type networks. A telephone interface installed at the customer's premises converting analog signals from the customer's in-home wiring to a digital signal, which is then sent over the cable connection to the company's Cable television headend switching center. The signal is then sent on to the public switched telephone network (PSTN). Cable telephone provides another revenue stream for cable television system operators and gives the consumer the convenience of combing several services on a single bill - such as paid television, internet and telephone services. [1] At times in the industry this is referred to as "triple play".

Contents

Emergency calls

The biggest obstacle to cable telephone service is the need for nearly 100% reliable service for emergency calls. PacketCable, one of the emerging standards being developed for digital cable telephony, seems to be the most promising and able to work with the quality of service demands of traditional analog telephone service.

Advantage

The biggest advantage to digital cable telephone service is similar to the advantage of digital cable television, namely that data can be compressed, resulting in much less bandwidth used than a dedicated analog circuit-switched service. Other advantages include better voice quality and perhaps future integration to a VoIP network providing cheap or unlimited nationwide and international calling. In most cases, digital cable telephone service is separate from broadband Internet access service being offered by many cable companies and does not rely on IP traffic or the Internet.

Disadvantage

One possible disadvantage to digital cable telephone service is similar to a disadvantage of cable Internet access, namely that the medium is shared, which could result in occasional delays and drops when high volumes of bandwidth are used or in some cases shared with entire neighborhoods. These delays could be experienced during the "prime time" parts of the day, when heavy Internet usage and Internet streaming devices can make telephone calls on this system difficult. However, by utilizing Cable Lab's Packet Cable interface specifications, cable operators are able to diminish the effects of heavy internet usage on call quality. This is done by way of QoS provisions present in the Packet Cable specifications. [2]

The second disadvantage it that this service requires power at the subscriber's end. In an emergency, if mains power is lost and without the battery backup unit provided at an additional cost by the cable provider, this telephone service ceases to function. Traditional landline service from phone companies supply phantom power over the communication wires and therefore keep attached devices operational.

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<span class="mw-page-title-main">Integrated Services Digital Network</span> Set of communication standards

Integrated Services Digital Network (ISDN) is a set of communication standards for simultaneous digital transmission of voice, video, data, and other network services over the digitalised circuits of the public switched telephone network. Work on the standard began in 1980 at Bell Labs and was formally standardized in 1988 in the CCITT "Red Book". By the time the standard was released, newer networking systems with much greater speeds were available, and ISDN saw relatively little uptake in the wider market. One estimate suggests ISDN use peaked at a worldwide total of 25 million subscribers at a time when 1.3 billion analog lines were in use. ISDN has largely been replaced with digital subscriber line (DSL) systems of much higher performance.

<span class="mw-page-title-main">Telephone</span> Telecommunications device

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PacketCable network is a technology specification defined by the industry consortium CableLabs for using Internet Protocol (IP) networks to deliver multimedia services, such as IP telephony, conferencing, and interactive gaming on a cable television infrastructure.

<span class="mw-page-title-main">Triple play (telecommunications)</span>

In the field of telecommunications, the concept of triple play service refers to the provision of three essential services — high-speed broadband Internet access, television, and latency-sensitive telephone services — all delivered over a single broadband connection. This approach emphasizes the convergence of multiple services by a single supplier, aiming to enhance user convenience and streamline service delivery.

In telecommunications, cable Internet access, shortened to cable Internet, is a form of broadband internet access which uses the same infrastructure as cable television. Like digital subscriber line and fiber to the premises services, cable Internet access provides network edge connectivity from the Internet service provider to an end user. It is integrated into the cable television infrastructure analogously to DSL which uses the existing telephone network. Cable TV networks and telecommunications networks are the two predominant forms of residential Internet access. Recently, both have seen increased competition from fiber deployments, wireless, mobile networks and satellite internet access.

The following outline is provided as an overview of and topical guide to telecommunication:

A managed facilities-based voice network (MFVN) is a communications network managed, operated, and maintained by a voice service provider that delivers traditional telephone service via a loop start analog telephone interface. MFVNs are interconnected with the public switched telephone network (PSTN) or other MFVNs and provide dialtone to end users. Historically, this was provided by equipment at Bell company central offices, however today's MFVNs can include a combination of access network, battery-backed customer premises equipment (CPE), network switches and routers, network management systems, voice call servers, and gateways to the broader PSTN.

References

  1. Richard Grigonis (ed) Cable Telephony in Computer Telephony Encyclopedia, Focal Press, 2000 pp.68-69
  2. , PacketCable™ Dynamic Quality-of-Service Specification.