Passive optical network switchable between an operational mode and a diagnostic mode
First Claim
1. A head-end station for a passive optical network system, the head-end station including means to transmit and receive diagnostic signals and TDMA data frames comprising a header portion and a plurality of basic frames, each basic frame comprising a plurality of traffic bits and a plurality of control bits, the head-end station further including means for detecting an abnormality in an operational mode and for causing the head-end station to switch between the operational mode in which it transmits and receives TDMA data frames and a diagnostic mode in which transmission of data frames is terminated and wherein said head-end station generates and transmits a diagnostic signal onto the passive optical network system and detects any return of the diagnostic signal.
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Accused Products
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.
38 Citations
21 Claims
- 1. A head-end station for a passive optical network system, the head-end station including means to transmit and receive diagnostic signals and TDMA data frames comprising a header portion and a plurality of basic frames, each basic frame comprising a plurality of traffic bits and a plurality of control bits, the head-end station further including means for detecting an abnormality in an operational mode and for causing the head-end station to switch between the operational mode in which it transmits and receives TDMA data frames and a diagnostic mode in which transmission of data frames is terminated and wherein said head-end station generates and transmits a diagnostic signal onto the passive optical network system and detects any return of the diagnostic signal.
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17. A method for operating a head-end station of a passive optical network, said method comprising the steps of:
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transmitting from the head-end station TDMA data frames of optical signals, said data frames including a header portion and a plurality of basic frames, each basic frame having a plurality of traffic bits and a plurality of control bits; and detecting an abnormality in an operational mode and switching between (a) said operational mode in which the head-end station transmits and receives TDMA data frames of optical signals and (b) a diagnostic mode in which transmission of data frames is terminated and the head-end station generates and transmits a diagnostic signal onto the passive optical network system and detects any return of the diagnostic signal. - View Dependent Claims (18, 19, 20, 21)
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Specification