Paging is the collective term for telecommunications services with radio simplex transmission of short messages. The services of paging systems always go from the sender to the receiver and not in the opposite direction, are divided into call classes. There are four call classes: Tone, Numeric, Alphanumeric and Data.
There are paging systems that can receive and display voice signals (Voice Paging), tone signals (Tone Paging), numeric sequences and short texts (Display Paging). These call classes are offered in several call types, such as individual call, group call, collective call or destination call.
In the meantime, the classic paging service has become an information service by offering value-added paging services. For example, stock exchange news, weather or traffic information can be transmitted. Small handy receivers with alphanumeric display, memory, alarm facility, overwrite protection and other facilities serve as mobile paging receivers (pagers). The transmission of paging calls can be done with different address types as single call, group call and collective call. Most paging systems use the POCSAG code for signaling.
In Germany, well-known paging services are Eurosignal, Cityruf later Qbic, Scall, Quix, Inforuf, Omniport, TelMI, Radiotext and ERMES. Work is also underway to launch worldwide paging services via satellite, such as Inmarsat-Paging(Inmarsat-D).