Polling system for a duplex communications link
US4251865A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 8, 1978 |
| Grant date | Feb 17, 1981 |
| Priority date | — |
| Expiry date | Dec 8, 1998 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG06F13/22
- WIPO fieldComputer technology
- WIPO sectorElectrical engineering
Abstract
Channel efficiency in a communications link between a controller and multiple portable units is increased by polling the active units and a set number of inactive units in a sequence where a "poll" consists of sending the binary coded address of the portable unit. The stream of transmitted data bits is only interrupted by a response from the portable unit, then resumed at the end of the response or a given portion of the response. During the reception of the response, certain other types of messages can be sent out by the controller. Portable responses can be automatic responses as to status, etc., or can be data initiated by the operator of the portable unit keyboard and stored in the portable unit memory until "armed" by the operator, then automatically transmitted to the controller when the portable unit address is received.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.