| 摘要 |
<p>Transient signal elimination circuitry (11, 14) disposed in a local communications loop extending from a subscriber telephone (15) to a telephone central office (10), couples ringing and on-hook and off-hook signals through the loop after removing transients in these signals. The circuitry also isolates the telephone subscriber and central office from the local loop until an off-hook signal is detected and restores this isolation when an on-hook condition exists at the telephone subscriber. In this manner, the local loop can be simultaneously used for both voice communications and a second information signal with each signal capable of occupying the same bandwidth. These signals can operate independently of each other.</p> |
