Coax Adapter Uhf

Coax Adapter Uhf

Terrestrial television networks multimedia services over cable

Cable television (TV) broadcast networks provide TV television households for cable TV. Digital TV in VHF and UHF frequencies from 47 MHz to 862 MHz each channel Television occupies 6 MHz of bandwidth and QAM modulated 64/128/256 before combining with all other channels at the head of cable TV. The coaxial cables are used to deliver RF signals to television households. The frequency band below 47 MHz is used for carry the return traffic of subscribers to cable television header.

For the cable television network delivery of broadband services data, a set of communication interfaces and network cable standards support the call operation target = "_new"> DOCSIS (Data over Cable Service Interface Standards) are developed by the cable industry. There are four versions of the DOCSIS, versions 1.0, 1.1, 2.0 and 3.0. DOCSIS 1.0 allows cable operators to provide Internet access up to 36 Mbps download its HFC (Hybrid Fiber Coax) networks. Version 1.1 adds QoS (Quality of Service) to enable the capacity of cable television networks to offer voice services and streaming services (IP multicast). Version 2.0 improves the download speed (30 Mbps maximum) 64 and QAM modulation bandwidth 6.4 MHz channel upstream to meet the increased demand for symmetrical services (eg IP telephony). DOCSIS 3.0 increases download speed channels large (up to 160 Mbps) and upload speeds (up to 120 Mbps) for multi-link upstream and downstream. Version 3.0 also introduced support IPv6.

PacketCable standards is another cable industry developed to provide packet voice, video and other multimedia services over broadband HFC cable networks. PacketCable is a set of protocols developed to provide improved QoS Communications services using packet data transmission to a consumer's home on the cable network. PacketCable network architecture support toll quality target = "_new"> VoIP (Voice over IP) and allows you to connect a traditional phone using an analog adapter integrated multimedia terminal (EMTA). Compatible with a capacity of primary and secondary backup battery residential voice line. PacketCable DOCSIS operates 1.1/2.0 QoS support capabilities and SIP (Session Initiation Protocol) in version 2.0. While early online services offering products for PacketCable voice and packaging Video packet, the long-term family encompasses a range of services based packages such as virtual private networks (VPNs), time real sessions of interactive video games, multimedia phone, interactive multimedia streaming.

Two main elements are the modem Cable DOCSIS (CM) to the hypothesis of subscribers and the Cable Modem Termination Systems (CMTS) in the headend of the cable operator. DOCSIS specifies physical interfaces and the MAC layer for communication between the CM and CMTS. PacketCable networks use IP as a basis for robust multimedia architecture. PacketCable architecture supports the functions of end to end services, including signaling, media transport variable QoS levels, security, provision of client device, billing and other functions of network management. PacketCable VoIP phone service uses a managed IP network instead of the public Internet to carry voice traffic. PacketCable specifications for Voice over IP (VoIP) describe the functions base should be consolidated into a class 5 central office switch. These functions can be deployed across multiple components or may be grouped in a single element, leading to a low cost, highly flexible and scalable distributed architecture.

With the deployment the architecture of DOCSIS and PacketCable, cable operators can become service providers in full "triple play" of voice, data and multimedia services. Cable operators can also use their cable network to provide service such as CableHome control Remote management and diagnosis of client home network (router, firewall, network address translation, the secure software download etc.) and other devices.

About the Author

Paul Ngai, P.E. is an engineering consultant specialized in Telecommunications Network and Systems. He is also the principal of Network Systems Technologies LLC (http://www.nstecs.net), a telecommunications consulting firm provides planning, analysis, design, testing and operation support services.