Telephone regulator circuitry
US4495382A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 23, 1982 |
| Grant date | Jan 22, 1985 |
| Priority date | — |
| Expiry date | Apr 23, 2002 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04M1/6025
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
This invention provides a single integrated circuit device which replaces the non-integrated "encapsulated circuit" of the standard prior art telephone set. The circuit of this invention achieves proper D.C. regulation of the telephone line, by presenting one of several possible D.C. impedances to the telephone line when the telephone set is in the off-hook condition. The circuit of this device provides such regulation by varying the gain relationship of the telephone set for various distances from the central switching office, thereby maintaining a rather uniform signal amplitude in a plurality of telephone sets located at various distances from the central switching office. In one embodiment, this is done using a novel regulator substantially completely formed as part of a single integrated circuit chip containing a receiver amplifier, transmitting amplifier, dialing circuitry and ringing circuitry. The use of integrated circuit technology allows many of the circuit components to be formed in a balanced manner thereby substantially improving the audio quality achieved with this invention compared to prior art telephone sets. The transmitter amplifier of this invention allows the …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.