Composite ringing and coin control voltage detector and method
US4962520A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Dec 8, 1989 |
| Grant date | Oct 9, 1990 |
| Priority date | — |
| Expiry date | Dec 8, 2009 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04M19/02
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
In a telephone system, a composite detection circuit and method for use in mechanized loop testing to detect both AC ringing and DC coin control voltage at a test access unit. An equalization circuit distinguishes between the two voltages and selectively amplifies the DC components of the voltages, thus amplifying the positive DC coin control voltages out of the detection range of the negative AC ringing voltages and vice versa. Two distinct outputs indicate either a positive or negative voltage detected. Two identical circuits are used, one on the ring line and one on the tip line, to detect positive and negative ringing and coin control voltages.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.