Video Telephone for PSTN

Teiji Okamoto, Ph. D., Multimedia Systems R&D Division, Hitachi, Ltd.
Toyota Honda, Multimedia Systems R&D Division, Hitachi, Ltd.
Masanori Yoshino, Consumer Products & Information Media Systems Group, Hitachi, Ltd.
Masanori Kamiya, Multimedia Systems R&D Division, Hitachi, Ltd.


Video telephones are one of the multimedia products supported by the advance of image compression and digital communication technologies.

Hitachi has produced and marketed all-in-one type video telephones for integrated services digital network (ISDN) in advance of other companies.

These products take advantage of the high speed and ease of use of ISDN lines. Even though the speed is somewhat slower, the user needs of the approximately 50,000,000 public switched telephone network (PSTN) lines in the country are great.

With this in mind, the video telephone was developed with AT & T for PSTN lines.

The goal of this development was not simply use as a video telephone. Rather, the product was developed presupposing applications to various multimedia systems requiring simultaneous two-way communication of video, picture, voice, and other data.

In particular, in addition to simple video functions, by including functions such as transmission of high quality pictures, free terminal control by connection to a personal computer, and remote control by other terminals, the structure is flexible and can adapt to the scale of the system.

© Hitachi, Ltd. All rights reserved.