Receiver having an interface with a sub-system
US4797919A · kind A · utility
Assignees
Inventors
Key dates
| Filing date | Nov 25, 1986 |
| Grant date | Jan 10, 1989 |
| Priority date | — |
| Expiry date | Nov 25, 2006 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04N21/4623
- WIPO fieldAudio-visual technology
- WIPO sectorElectrical engineering
Abstract
A receiver having an interface arrangement for connection between a television circuit and a conditional access sub-system conveys data via a bus having a four frame bus cycle period with a bit rate corresponding to the line rate. During a first part of the bus cycle period data is conveyed from the receiver to the sub-system sequentially as follows: PA0 i. an address block of 1 byte with the unique address of the sub-system with which the receiver is in communication, PA0 ii. a status block of 1 byte providing status information for the following blocks in the first part, PA0 iii,iv,v. three data blocks each of 93 bytes and each containing an entitlement message, PA0 vi. a keying block of 1 byte conveying keyboard or remote control commands, and PA0 vii,viii. a further block of either 1/2 byte (vii) or 21/2 bytes (vii+viii) conveying frame count information. During the second and remaining part of the bus cycle period which comprises 30 or 28 bytes, depending on the length of the further block, data is transmitted from the sub-system to the receiver.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.