PORTABLE TELEPHONE SET, KEY LOCK METHOD USED FOR IT, AND RECORDING MEDIUM RECORDING ITS CONTROL PROGRAM

PROBLEM TO BE SOLVED: To provide the portable telephone set where wrong operation of keys is prevented by key lock in the case of housing the portable telephone set with an active power supply and in an on-hook state and the key lock is easily released. SOLUTION: A control section 1 uses a timer 6 to count a time till a key operation is made to a key section 2 after the end of key operation. When the timer 6 exceeds a time set by a time setting section 7 in advance while no key operation is made to the key section 2, the control section 1 invalidates a signal other than that from an (a) key 13 to limit the key operation. When the (a) key 13 is depressed in the key operation limiting state, the control section 1 judges it to be release of the key operation limit and restores the keys to be a key operation enable state.