A method and apparatus for framing data in digital transmission lines automatically recognizes a framing format. The apparatus preferably includes a frame alignment apparatus that can recognize any one of a number of predetermined framing formats created by framing information on an input signal. The frame alignment apparatus outputs an aligning signal to an output frame counter, which counts the data and framing information on the input signal and outputs a frame synchronization signal according to the framing format. The input signal is also coupled to an output apparatus that outputs the input signal at the clock rate of a terminating apparatus. The frame alignment apparatus preferably includes a plurality of pattern recognizers able to recognize at least one of the framing formats and a storage apparatus for storing counts of successive data and framing information that match a framing pattern. The counts are preferably used to identify the flaming information on the input signal and the flaming format.