Signaling protocol interface channel unit
US4623760A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Oct 28, 1983 |
| Grant date | Nov 18, 1986 |
| Priority date | — |
| Expiry date | Oct 28, 2003 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04Q11/04
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
Disclosed is a channel unit for directly interconnecting a toll office multiplex line and a terminal unit line such as that of a private branch exchange (PBX) or a telephone station set, thereby eliminating the normal local end office interconnection. In particular, the channel unit interfaces the different signaling protocols of the two lines and generates call progress controls signals such as dial tone and audible ringing which are normally generated by the local end office. The channel unit comprises a converter for each line for converting the electrical interface signals representative of the busy and idle conditions of the line to logic levels also representative of the busy and idle conditions of the line. A predetermined series of these logic levels form a control signal that indicates the state of a call on the line. Since the control signal indicative of the state of the call on one line is typically not useable by the other line, a microprocessor included in the unit generates a second control signal to advance the state of the call on the other line to an equivalent call state. An additional converter then converts the logic levels of this second control signal to the …
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.