Method and apparatus for optical media access protection in a passive optical network

In Ethernet networks that operate over shared copper media, e.g., IEEE 802.3 standards for 10Base5, 10Base2 and 10BaseT, apparatus in the network access device for a connected terminal typically includes a so-called "jabber" circuit that monitors the length of transmission into the copper media for that individual terminal. If the continuous transmission of the individual terminal exceeds an accepted maximum length of time many times a maximum size packet, that terminal is disabled for a quiet period of, e.g., 500 milliseconds and then usually is allowed to resume transmission. An apparatus and method is disclosed for protecting access to a shared medium in an optical communications system which has plural remote terminals coupled to a central terminal over the shared medium. According to one aspect, if an optical transmitter for an individual remote terminal is active for a first prescribed time interval when it has not been enabled for such transmission, the optical transmitter is disabled. According to another aspect, the continuous time that an individual terminal is enabled to transmit onto the shared medium is monitored. If the enabled transmission for the individual terminal exceeds a second prescribed time interval, the optical transmitter for the individual terminal is disabled.