| 摘要 |
<p>A portable two wire line test set having a selfcontained source of electrical energy for powering a hybrid circuit and first and second amplifiers. The first amplifier receives and amplifies voice signals transmitted over the two wire line and the second amplifier amplifies and transmits voice signals over the two wire line. Transducers are connected to both amplifiers to convert signals to audible sounds and vice versa. In an alternative embodiment a third tuned amplifier is included for detecting and amplifying a signal in a predetermined frequency range so that the identity and condition of particular two wire lines may be determined.</p> |
