| 摘要 |
<p>Two devices are connected via a single analogue signal path such as a public telephone line in such a manner as to permit the users to talk to each other while interactively modifying an image which is presented to both users simultaneously. Each device multiplexes a reduced voice signal, e.g. from a vocoder (3), with a control signal indicative of changes to make to the image, and transmits the composite signal via a modem (4). The devices either respond to both image signals to modify the image (e.g. if they are word processors responding to key presses) or to the same selected one of the signals as determined by a protocol (e.g. if a spreadsheet is being altered by only one user at a time). Each device may be stand alone, such as incorporating a computer or facsimile machine, or an adaptor for existing such machines; it may be inserted between a telephone set and the line, or have separate audio transducers and connect to the line via a telephone set.</p> |
