| 摘要 |
<p>The method requires a technician and an unskilled assistant, one at each end of the line. A transmitter, controlled by the technician, sends a sinusoidal signal along a pair of wires to a receiver at the other end, controlled by an assistant. The assistant immediately relays the results to the technician by telephone. The procedure is repeated in the two directions for a four-wire line, and unskilled assistant receiving directions from the technician over the telephone. The transmitter used generates as 800 Hz sine wave signal at a constant and non-adjustable level. The unskilled part of the work may be undertaken by the telephone subscriber himself.</p> |
