Measurement of transmission quality of a telephone channel
US4862492A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Oct 26, 1988 |
| Grant date | Aug 29, 1989 |
| Priority date | — |
| Expiry date | Oct 26, 2008 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04Q3/0016
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
Apparatus and method for measuring the transmission quality of a telephone line, for example, a telephone line connected between two voice processing systems. The apparatus includes means for generating a predetermined sequence of DTMF pulses having predetermined amplitude values and for transmitting them over a telephone line; means for receiving DTMF pulses from a telephone line and determining the value of each pulse; means for counting the number of received DTMF pulses; and means for comparing the number with a predetermined threshold value, whereby the telephone line is determined to have acceptable transmission quality if the number exceeds the predetermined threshold value. Further, in a preferred embodiment, the predetermined sequence of DTMF pulses comprises four groups of ten (10) DTMF pulses, each of which groups has succeedingly lower amplitude.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.