Abstract: For use in access-control apparatus, the character-to-key assignment in a keypad for inputting an authorization or identification code is changed at specified events so as to scroll the array of assigned characters. The security offered by the device against the inputted characters being surreptitiously "read" by observation of the keys actuated is thereby enhanced but without the operating difficulties encountered with keypads in which the character-to-key assignment is changed on a purely random basis.

Abstract: A personal portable telephone (11) allows the user access to the cellular radio network via a number of different gateways including a communal unit (15, 16), user's mobile telephone set (9), home telephone (13) or office PABX (14). The telephone (11) can also be used as a paging unit for use within the cellular radio network. The communal radio unit (15) is a multi-channel arrangement capable of servicing a large number of personal telephones within its service area which is small compared to that of a normal cellular radio cell. Communal units (15) may be transportable and located in public areas such as railway stations, airports and on trains or coaches. The telephone (11) automatically transmits its identification number to a gateway (9, 13, 14, 15, 16) when it enters its service area enabling the subscriber to be accessed by callers without their knowing his whereabouts.