Systems and methods for transmitting data having a rate indicated by an associated clock signal, using a fixed rate transmission system are disclosed. One embodiment of the invention includes an unknown rate to fixed rate transmitter configured to receive unknown rate data and a clock signal that indicates the rate of the unknown rate data, and to transmit data at a fixed rate over a fixed rate link, a fixed rate to unknown rate receiver configured to receive fixed rate data including the unknown rate data via the fixed rate link, and to transmit the unknown rate data, and a recovered clock signal. In addition, the unknown rate to fixed rate transmitter is configured to insert idle data between the fixed rate data so that transmitting the combined unknown rate and idle data at the fixed rate over the fixed rate link results in the unknown rate data being transmitted over the fixed rate link at a rate corresponding to the rate indicated by the clock signal, and the fixed rate to unknown rate receiver is configured to accumulate the unknown rate data and generate a recovered clock signal based upon the rate at which the unknown rate data is accumulated by the fixed rate to unknown rate receiver.