Digital data loopback device
US5442697A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Nov 29, 1993 |
| Grant date | Aug 15, 1995 |
| Priority date | — |
| Expiry date | Nov 29, 2013 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L1/243
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
The need to equip a digital data service termination with the ability to decode digital loopback commands is obviated by a relatively simple hardware modification of a four wire telephone circuit connecting an office channel unit and customer premises equipment. In addition, the signal processing and test control firmware of the office channel unit equipment (OCU DP) is modified so as to realize a simplified circuit configuration for performing loopback testing of the four wire circuit. The hardware modification of the four wire circuit connecting the office channel unit and the customer premises involves the use of a sealing current-dependent relay circuit that responds to respectively different sealing current flow states: normally; interrupted; and reversed, as converted by the OCU DP. The present invention is particularly useful in subscriber loop circuits that are less than 10,000 feet in length, whereby the need for additional amplifier and noise reduction components is obviated.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.