Optical interface.

摘要

The optical interface (28a-h) comprises an optical transmitter section (65,65a,75,125,135,145) and an optical receiver section (200). The optical transmitter section (65,65a,75,125,135,145) receives data in an (NRZI) format from a LAN controller when the interface (28a-h) is part of a remote node. The transmitter section (65,65a,75,125,135,145) converts the non-return to zero inverted data to an AMI format. An LED driver circuit (135) smooths out and extends the AMI data and uses it to drive an LED (160). The LED driver (135) alternately drives the LED (160) from a fifty percent reference output level to zero percent output and one hundred percent output corresponding to alternate positive-going and negative-going transitions of the data. The receiver section (200) has a light sensitive detector and preamplifier (202) which receives optical signals encoded with digital data and generates corresponding electrical signals which are processed by a peak pulse detector (224) of the type used to detect signals generated by the read/write heads of magnetic disk media. The disk pulse detector (224) generates unipolar digital signals corresponding to the AMI signals. A decoder (320) converts the unipolar digital pulses to NRZI format. The NRZI data is communicated to a LAN controller when the optical receiver is part of a remote optical interface (28a-h) and to conventional LAN hub circuitry when it is part of a hub optical interface. The LED driver circuit (135) comprises the entire transmitter section of a hub optical interface and receives data for transmission directly from the hub LAN circuitry.