Remote supervisory control system
US5049872A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 31, 1990 |
| Grant date | Sep 17, 1991 |
| Priority date | — |
| Expiry date | Aug 31, 2010 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04Q9/14
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A slave station at an end location of a transmission route is responsive to a polling signal issued from a master station such that if there exist data to be sent to the master station, the slave station transmits a code with a "busy" token and specifying the data to a slave station at the next upper location; and if there do not exist data to be sent to the master station, the slave station transmits a "free" token to the slave station at the next upper location. When the slave station at the upper location receives the "busy" token from the station at the lower location, the slave station at the upper location relays the entire codes receives. If the "free" token is received and when there exist data to be sent to the master station, the slave station replaces the "free" token with the "busy" token and subsequently sends the obtained data; and if there do not exist data to be sent to the master station, the slave station relays the "free" token to a slave station at the next upper location or the master station.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.