Jargon buster

Open Systems Interconnection (OSI) is a model that standardises the communication functions of a telephone or computing system. There are 7 key layers in the model ranging from the physical layer through to the application layer.

Openreach (OR) are the department of BT which maintains the telephone cabling, cabinets and exchanges within the UK that connect nearly all homes and businesses.

see Openreach

see Open Systems Interconnection

A technique in which a message is broken into smaller units called packets, which may be individually addressed and routed through the network, possibly using several different routes. The receiving-end node ascertains that all packets are received and in the proper sequence before forwarding the complete message to the addressee. 

see Private Branch Exchange

Plain Old Telephone System (POTS) is the predecessor term to Public Switched Telephone Network (PSTN). It is the collection of analogue phone lines whose main purpose is to transmit voice calls.

see Power Over Ethernet

A postal, telegraph, and telephone service (or PTT) is a government agency responsible for postal mail, telegraph, and telephone services.

see Plain Old Telephone Service

Power Over Ethernet (POE) is the ability to provide power to a device across a network cable without the need for a separate power cable.

A Power Supply Unit (PSU) is a separate cable and/or unit commonly with a UK mains plug used to power a device.