| 摘要 |
<p>A device (1) for protecting a telecommunications apparatus against an abnormal transient voltage signal received via a telecommunications line (2, 3) comprises means (16, 18, 20, 22, 26) for selectively suppressing the transient voltage signal from other normal communications signals. The suppression means (16, 18, 20, 22, 26) are responsive to the frequency of the transient voltage signal rather than its voltage. Overvoltage protection means (12, 14) may also be provided for suppressing transient and continuous overvoltage signals present on the telecommunications line (2, 3). <IMAGE></p> |
