| Word | Description |
| Pair gain | A technology that ‘squeezes’ two telephony circuits into the capacity normally allocated to an individual circuit. This has no appreciable impact on voice services, but effectively halves the capacity that can be achieved on modem circuits. Instead of a peak of 56kbps, users connected by pair gain circuits can typically only achieve around 28kbps. |
| PDF (portable document format) | A file format designed by Adobe, and is a popular way of formatting documents, which can be viewed and printed on multiple platforms through the freely available Adobe Acrobat Reader. |
| PGP (pretty good privacy) | PGP is a program used for encrypting and decrypting email and data files. |
| PON (passive optical network) | Strictly speaking, a PON is a purely optical network – that is, without any ‘midstream’ electronics to boost signals or multiplex multiple customers onto a common fibre. As such, a point-to-point optical fibre is a PON. However, more commonly the term refers to an optical network architecture where an optical splitter distributes light between one source and many destinations (downstream), or multiplexes light from multiple sources to one destination (upstream). The most common split ratio is 32:1. |
| POP (point of presence) | Used by ISPs, it means giving local access to a network. |
| PPP (Point to Point Protocol) | Commonly used for connecting two or more computers. |
| Protocol | In IT, a protocol is the set of rules that describe a format or method to enable the transmission of data between nodes on a computer network. |
| Proxy | A machine used as a storage area for commonly accessed files, and is used to speed up the transfer of information from the Internet. |