Telecom Terms and Concepts Introduction to terms Telecom

Telecom Terms and Concepts Introduction to terms

Telecom and Computers are merged to deliver data l l l Tele – distance Communications Transfer of information from a transmitter to a receiver

Many parts come together to provide a path

Some terms to know Transmitter Receiver Circuit Link Line Trunk Channel Switch Network

Transmitter l l l Also known as sender or source Originates the information transfer Samples include: –Voice telephones –Data terminals –Host systems –Video cameras

Receiver l l l Also known as the sink Destination of the information transfer Samples include: -Telephones -Host computers -Video Monitors

Circuit l l l A communications path, over an established medium, between two or more points, from end to end, between transmitter and receiver Generally implies a logical connection over a physical path May be for transport or access

Access Circuits l From customer premise to the edge of the carrier network

Transport Circuit l Employed at the core of the network for longhaul transmission

Some types of Circuits l l l Simplex – (one way) Half-duplex – (two way, but only one at a time) Full-duplex – (two way, at the same time)

Link l l A two-point segment of an end-to-end circuit (e. g. , from a terminal to switch) Circuits generally consist of several links

Line l l l Several definitions can make this term confusing. PBX – station line – connection between the PBX switch and the station users terminal equipment Rate and Tariff (Telco) – line refers to the local loop connection from Telco CO (Central Office) to the user in support of CPE (Customer Premise Equipment)

Lines in Telco-speak l Examples – – l l Single phone line to a business A multi-line set Usually voice grade – although this is changing as the infrastructure matures For Telco’s the line side is the users access to the network – for the other side there are Trunks

Trunk l A communications circuit, available to share among multiple users, on a pooled basis with contention managed by an intelligent switching device. – NOTE: this is not the same switching device as in a Local Area Network – i. e. Layer 2

Trunks Connect Switches l l l Tie Trunks – connect PBX switches in a private, leased line network Central Office Exchange Trunks – connect PBX’s to Telco switches Interoffice Trunks – Connect CO Exchange groups

Trunk Groups l Groups of trunks serving the same special purpose. – – WATS (Wide Area Telecommunications Service DID (Direct Inward Dial)

Trunks are Directional l One way out -- Originating One way in -- Terminating Two-way – Combination

Channel l l A means of communication between transmitter and receiver A logical connection over a physical circuit to support a conversation

Switch l Establishes, maintains and changes logical connections over physical circuits – – Circuit Packet Frame Cell

Edge Switches l l Positioned at the edge of the network Users gain access via an access link

Core Switches l l Also known as Tandem Switches High capacity switches at the core to interconnect edge switches

Network l The fabric of elements which work together to support the transfer of information