| 摘要 |
The invention relates to a circuit arrangement for a signal conversion device in special digital telephone systems with external tone-dial signalling and internal DC signalling. Signalling data from tone-dial signals are transmitted via line-individual data-reading devices (DL1, DL2) to a microprocessor (MC) where they are converted into DC signals. Signalling data from DC signals are fed in similar fashion via these data-reading devices (DL1, DL2) to the microprocessor (MC) and are converted into signalling data for tone-dial signals. Signal conversion devices of this type are used in special telephone systems with mixed signalling methods. <IMAGE>
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