The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
May. 30, 1989
Filed:
Jan. 29, 1988
Norman J Donaghue, Jr, Plantation, FL (US);
Jay P Jayapalan, Hollywood, FL (US);
Rafael E Salcedo, Miami Springs, FL (US);
Racal Data Communications Inc., Sunrise, FL (US);
Abstract
An apparatus for providing passive bus communication in an ISDN without use of services of a central office includes a passive bus suitable for ISDN D-channel frame communication, the passive bus having an echo channel and having a plurality of terminal devices coupled to the passive bus. A receiving circuit is coupled to the passive bus for receiving D-channel frames containing a SAPI address transmitted from the terminal devices over the passive bus. A decoding circuit is coupled to the receiving circuit for decoding D-channel addresses transmitted from the terminal devices over the passive bus. The decoding circuit includes a circuit for determining if one of the D-channel frames from the terminal devices include a predetermined SAPI address. A switching circuit is coupled to and responsive to the decoding circuit, and implements a logical communication channel between two or more of the plurality of terminal devices when the D-channel frame includes the predetermined SAPI address. The switching circuit echoes D-channel frames over the echo channel of the passive bus for receipt by the terminal devices (TE) coupled to the passive bus and inhibits transmission of the D-channel frames to the central office when the D-channel frames include the predetermined SAPI address. The TE monitors the D-echo channel to receive the local passive bus communication in addition to contention resolution.