The term "PIPS Greenwich Time Signal" likely refers to the time signal provided by the PIPS (Post Office and BT Information Services) system at Greenwich, which is part of the United Kingdom. The Greenwich Time Signal, often known as the "BBC pips," is a series of six short tones broadcast at the top of each hour on BBC Radio. These tones help people synchronize their timekeeping devices with the official time.

The time signal consists of five short pips, each lasting one-tenth of a second, with a gap of one-tenth of a second between each. The sixth pip is longer, lasting half a second, and it is on the precise start of the new hour.

This time signal has been a feature of BBC Radio broadcasts since 1924, providing an audible reference for individuals to set their clocks accurately. It is particularly useful for those who need precise timekeeping, such as astronomers, navigators, and individuals involved in various professional activities where accurate timing is crucial.