Matsushita Electric Industrial Co., Ltd.

Panasonic Intellectual Property Management Co., Ltd.

Kouichi Iida

Tetsuya Ashizuka

Tetsuya Ashizauka

There is provided an intercom system which realizes high-quality image display and communication with low cost. In the intercom system, front door slave unithaving an attached camera and master unitare connected to each other through a two-wire cable, and communication between front door slave unitand master unitis performed with transmission and reception of an image signal. Front door slave unitpacketizes a control signal, an image signal, and a sound signal of front door slave unit, generates an uplink signal, and transmits the generated uplink signal to master unit. Master unitpacketizes a control signal and a sound signal of master unit, generates a downlink signal, and transmits the generated downlink signal to front door slave unit. Front door slave unitand master unitperform transmission of the uplink signal and transmission of the downlink signal in a manner of time division duplex using the two-wire cable.

Intercom system and communication method

In a facsimile apparatus having a magnetic tape recording apparatus for data storage and a buffer memory for data transfer to and from the recording apparatus, with the data being temporarily held in the buffer memory as respective blocks in a set of records, a synchronizing signal is inserted at the start of each recorded block of data, and the synchronizing signals are detected subsequently during playback of the recorded data. During playback, a buffer memory address generating circuit which specifies respective records and intra-record addresses for writing the playback data into the buffer memory, is reset to either the initial address of the current record or the initial address of the succeeding record each time a synchronizing signal is detected, in accordance with the position where the detection occurs within the addresses of the current record. The effects of an error in the playback data can thereby be limited to the data block in which the error occurs, without propogating to subsequent blocks.

Growing community of inventors

Fukuoka, Japan

Kouichi Iida