Electronic subscriber line connection circuit
US5097503A · kind A · utility
Assignee
Inventor
Key dates
| Filing date | Jan 29, 1990 |
| Grant date | Mar 17, 1992 |
| Priority date | — |
| Expiry date | Jan 29, 2010 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04M19/005
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
The connection circuit comprises a first differential amplifier circuit having its output connected to a first symmetrical amplifier circuit, a second differential amplifier circuit having its output connected to a second symmetrical amplifier circuit, a power supply and filter circuit for delivering power via a power supply series connection to the two symmetrical amplifier circuits, a balancing circuit, and a loop state signaling circuit. The two differential amplifier circuits are connected firstly to the output of a receive circuit and secondly to ground, and each wire of the line is connected directly via a respective resistor to a transmit circuit. Each symmetrical amplifier circuit is connected to one of the line wires via a contact of a ringing relay and a resistor connected in series. The power supply series connection includes a power supply transistor controlled by a signal indicative of the line being looped.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.