| 摘要 |
PURPOSE:To digitize a single telephone set and a single subscriber exchanger, by giving a new function other than call functions to a digital telephone set and making higher the functions. CONSTITUTION:A multifrequency dial signal consisting of a channel current from a transmitter 11 and the 1st output of a signal transmitter 14 overlaps at analop quantity at a coupler 12 and it is digitized at an A/D converter 13. A dial push button keyboard output being the 2nd output of the signal transmitter 14 and a binary monitoring control output such as on-hooking are made to bit parallel/serial conversion at an A/D converter 15. The output of the converter 13 and the coder 15 is transmitted after being allocated at a code multiplexer with synchronizing bits. A separator 20 receives signals from an exchanger and supplies a signal coding the analog quantity to a coupler 22 via a line 28 and a signal given in the binary format from the start to a decoder 25 respectively. The decoder 25 supplies one output (transmission tone, callout tone) to the coupler 22 as digital quantity and another output (callout signal, character data and monitor control signal) to a signal receiver 24. |
