Abstract: A protocol for fiber-optic communication systems, or other communication systems based on transmission of unipolar pulses having wide dynamic range provides for information to be transmitted in packets having a predictable time slot for each transmitter. The receiver for such protocol has a first relatively long RC time constant mode conditioned for reception of data packets whose time of arrival is well predictable and a second relatively short RC time constant mode conditioned for reception of asynchronous randomly received packets. In the relatively long RC time constant mode, each packet includes a preamble having a first clamp interval in which no pulse is transmitted, and a second clamp interval in which a continual pulse is transmitted. A transducer on the receiver translates the packets of pulses into differential electronic signals on first and second outputs.