| 摘要 |
<p>A telephone call cost monitor comprises a pick-up 15 connected to a detector 16, a calculator 18 and a visual display 19. A keyboard 11 is also provided to allow information, such as charge tariff information, to be introduced into the calculator. The monitor senses specific charge pulses, or other signal pulses passing through the telephone line, without electrical contact therewith, and generates cost information signals which can be displayed or further processed.</p> |
