SUBSCRIPTER EMERGENCY DISTINGUISHING METHOD FOR REMOTE INFORMATION SYSTEM

摘要

Thee subscriber alarm discriminating method for a remote information system includes the steps of: controlling an arbitrary subscriber telephone line to connect to an in-house utility; checking whether a first unaudible frequency is received or not; transmitting a second unaudible frequency for investigating the kind of trouble of the in-house utility if the first unaudible frequency is not received; checking the switching ratio if the first unaudible frequency; and discriminating the kind of trouble and transmitting the result to a host computer, thereby effecting the detection of trouble even during communication.