US Patent 7224492 Facsimile apparatus capable of detecting a line connection

A facsimile apparatus can properly detect whether or not the facsimile apparatus is connected to a line. The facsimile apparatus comprises a network control device formed of a semiconductor DAA device having a primary line control part driven by a local power supply and a secondary serial interface circuit communicating with said primary line control part through a photocoupler and a local power supply detecting part detecting a local power supply to said primary line control part. As a result, it is possible to detect whether or not the facsimile apparatus is connected to the line.