Selective signalling encoder/decoder for multipoint data communication networks
US4815105A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 7, 1987 |
| Grant date | Mar 21, 1989 |
| Priority date | — |
| Expiry date | Apr 7, 2007 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L25/03019
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
A selective secondary signalling encoder/decoder for multipoint data communications networks for use on transmission media such as telephone lines provides for selective signalling between a master broadcasting unit and however many slave units are in the network. The network functions by sending a standard (V-29) type modem training sequence and incorporating the address of the particular remote unit with which communication is desired in the data segment of the sequence. Compatibility is maintained with standard slave units that don't have this decoder by appending a sufficient number of marks to the address and message to allow for the standard starting value of a descrambler in the "data mode". When the segment is detected at each remote unit in the system, the address sent is compared to the address of the remote or slave unit. Upon a comparison match, together with a synchronism check and error checks, a valid message flag is set, indicating to the remote unit that it has received a command from the master site and thus the selected remote can be retrained or send a new sequence back to the master. Thus, instead of having to broadcast the same command to all remotes, individu…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.