Portable wireless telephone apparatus with use specific power monitoring

摘要

In a portable wireless telephone capable of providing a cellular mode which allows users to place or receive telephone calls through a cellular telephone network and a cordless mode which allows the users to place or receive telephone calls through an associated base unit of a cordless telephone, a battery voltage is monitored to check whether or not the battery voltage is so lowered that the cellular mode becomes inoperative. An LCD unit displays a low-voltage warning if the battery voltage is lowered down to such a low level. However, a micro computer equipped in this portable wireless telephone allows the users to use this portable wireless telephone as a cordless telephone. Accordingly, this portable wireless telephone can be still activated in the cordless mode even if it cannot be no longer used as a cellular telephone.