RADIO TELEPHONE APPARATUS

摘要

Radio telephone apparatus for use in a cellular mobile telephone system comprising means for alerting at least one of the users of the apparatus in response to a drop in signal strength of radio frequency signals received over the communication channel, when the apparatus approaches a boundary of the call service area. The signal strength is periodically checked to determine if it has fallen below a first predetermined signal strength and if so the user is alerted. When the signal strength falls below a second predetermined signal strength the apparatus causes a disconnection of the telephone link and returns to a standby mode.