Abstract: An object of the invention is to provide a monitor system for detecting occurrence of abnormal situation on the elderly living alone and the like, by using an inexpensive table tap alone, without modifying an electric appliance and a plug which are currently used. A table tap (100) contains an ammeter (103), a judgement unit (104), and a communication unit (105). After connecting an electric appliance which is currently used to the table tap, when the judgement unit (104) decides that the power consumption detected by the ammeter (103) is unusual, the communication unit (105) notifies a base station (109) that an abnormal situation occurs.

Abstract: An object of the invention is to provide a monitor system for detecting occurrence of abnormal situation on the elderly living alone and the like, by using an inexpensive table tap alone, without modifying an electric appliance and a plug which are currently used.

Abstract: A train of data blocks, each carrying digital data and ID data are produced from a reading head as a tape passes the cylinder. A memory having a plurality of sections is provided, and a plurality of counters are provided correspondingly to the sections. The digital data are stored in a memory section identified by the ID data. Each time the digital data for one block is stored in a section in the memory, a counter corresponding to that section is incremented, and each time the digital data for one block is read out from a section in the memory, a counter corresponding to that section is decremented. Thus, as long as counter repeats "0" and "1", the data block is properly stored and properly read. However, if any one of the counters shows a number other than "0" and "1", it is understood that the writing or reading has been carried out twice in a row for the same section in the memory. Thus, an error in the ID data can be detected.