The present invention is directed to data communication. More specifically, an embodiment of the present invention provides a technique for detecting loss of signal. An incoming data stream is sampled and a recovered clock signal is generated accordingly. An output clock signal of a higher frequency than the recovered clock signal is generated by a transmission PLL. The frequency of the recovered clock signal is compared to a divided frequency of the output clock signal. If a difference between the recovered clock signal and the output clock signal is greater than a threshold, a loss of signal indication is provided. There are other embodiments as well.