| 摘要 |
In a telephone handset, a plurality of which are connected to workstations or answering stations of predominantly multi-user dealing room systems, it is intended, in the case of connections which are on hold, to be able to identify by the presence of voice frequencies that the resumption of a call is desired. Within the handset, a speech recogniser connected in parallel with the receiver has an operational amplifier with a following band-rejection filter for audio frequencies and a threshold amplifier connected to it which, via a switching amplifier, activates a visual display element provided in the handset. If a multiplicity of connections are on hold, which are switched directly to handsets, fast and simple identification is enabled of the handset whose connection is intended to be switched to call mode, because the other party to the call sends an audible signal. With audible signalling only, the handset concerned cannot be identified as readily as with visual display.
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