In a paging system, the paging terminal, after accepting an incoming page and validating it, will encode the pager address and message into the appropriate paging signalling protocol. Various signalling protocols are used for the different paging service types, such as tone- only, tone and voice, etc.
Most paging networks are able to support many different paging formats over a single frequency.
The first format uses an analog transmission technique while the second uses a digital transmission technique to transfer information to the pagers. In digital transmission, the signal to be transmitted is first digitized, i.e. it is converted into a form where it is represented by a series of ones and zeros. Digital transmission has many advantages over analog transmission, a very important one being its better performance in the presence of noise. In the following, various analog and digital coding formats are described and compared. In this format, a sequence of audio tones is used to identify each pager.