| 摘要 |
<p>An apparatus is provided for detecting single and/or multiple cadenced tone progress status of a telephone call in any one of a plurality of telephone networks. A set of parameters for each of a multiplicity of predetermined single and/or cadenced tones in which some call progress status having multiple different sets of parameters for the same call progress status are stored in memory. Parameters of the cadence(s) of a valid tone present on the telephone line are measured and compared whith the multiplicity of sets of parameters stored in the memory (20, 42) to establish the presence of the call progress status represented by the corresponding cadenced valid tone. For tones having multiple cadences, the measured parameters of each cadence is compared with a corresponding set of cadence parameters of the memory to establish the presence of the call progress status represented by the multiple cadenced tone.</p> |
