| 摘要 |
The combined keyboard incorporates a signalling selection system that is connected to the decimal and multifrequency signalling electronics, permitting the decimal signalling of a telephone number and at the same time, once communication has been established, permitting the transmission of multifrequency codes, this being able to be effected by the on-hook and non-on-hook operation of the telephone or also by the pulsing of a specific key, thereby switching the decadic signalling system to the multifrequency system. <IMAGE>
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