Abstract: A monitoring apparatus that captures data in a router into a monitoring apparatus to cope with a communication abnormality in a monitoring system that uses the router, a modem, and a network. The monitoring apparatus comprises input modules 343, 345 for being input with a signal from a monitored object 303; a CPU module 341 for processing the signal from the input modules 343, 345; a communication module 342; a data bus 352; and a power module 340. The communication module has two connectors 204, 206 or more each connected to the network; a connection terminal connected to a power supply buss 351; a connection terminal connected to the data bus 352; a memory; and a CPU.

Abstract: A monitoring apparatus having a plurality of communication units, each of which incorporates therein a communication control section, a control section and a memory section, and executes programs for communicating with monitoring terminals via a communication network; and memory units, each storing data therein. The monitoring apparatus has a function that at least one of the plural communication units decides on whether or not the operations of the other communication units are normal, depending on the contents of its communications with the other communication units, and also a function that the decision is displayed on a personal computer placed outside the monitoring apparatus.