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:
Aug. 20, 1996
Filed:
Feb. 28, 1995
British Telecommunications public limited company, London, GB;
Abstract
A head-end station for a passive optical network system arranged to transmit and receive TDMA frames having a header portion and a plurality of basic frames, each basic frame includes traffic bits and control bits. The head-end station includes a data transmitter which assembles and transmits downstream frames and also generates a diagnostic signal for transmission in a downstream frame, the station being switchable to a diagnostic mode in which it transmits the diagnostic signal in a downstream frame in the absence of other traffic, and also including a data receiver which receives upstream frames and detects a return of the diagnostic signal. In a preferred example, the head-end station may transmit a diagnostic signal in the header portion of each downstream frame. Also, in a test mode the transmit signal is looped back to the receiver to enable testing of the transmit receive function. Loop back is provided at three levels, namely the transmitter drive level, the monitored output level and at the laser output receiver input level.