| 摘要 |
<p>A relay control circuit to control a path of the voice and image signals for a picture telephone comprises a telephone interface circuit (11) and a matching transformer (13) for matching a first telephone line and a MODEM (1), connected to the first telephone line, a first relay (RY1) connected to a second telephone line, temminals (2f,1g) of a second relay (RY2) connected to a hook switch (10) and the telephone interface circuit, and a ring detector (7) connected to a third relay (RY3). The output signals (21,22,23) of a relay driver (2) control the first, second and third relays.</p> |
