| 摘要 |
A cable television distribution network has a central store and control unit 1 connected to a number of main transmission lines 2 from which are tapped spurs 3 linked to domestic television receivers (of which only one, 4, is shown). In operation, the central unit 1 sends command signals in teletext format down the main transmission lines 2 to operate on either the receiver 4 or a remote device (via the receiver 4) e.g. keyboard 5, heating system 6 or security system 7; also the unit 1 can process any signals returning from receiver 4 (including any originating from the remote devices) and take appropriate action. |
