| 摘要 |
<p>System for distributing environmental sound/paging via telephone extensions of a PABX, comprising a base station (2) serially connected to the PABX and the lines of the telephone extensions. The base station (2) injects a frequency-modulated carrier into the telephone-extension lines; according to a selected option this carrier contains either an environmental sound signal or a paging signal. A terminal station (3), serially installed between the extension line and the telephone set, receives the modulated carrier injected by the base station (2), demodulates it and retrieves either the environmental sound signal or the paging signal, amplifies it and converts it to sound via a sound transducer. The terminal station (3) also allows independent volume control for paging and environmental sound.</p> |
