APPARATUS FOR DECODING FRAMES FROM A DATA LINK

An apparatus for decoding frames from a data link including a multiple entry expect/mask buffer an input for receiving multiple character frames, a comparator for comparing characters received from the data link with expected characters in the expect/mask buffer as masked by a mask also in the expect/mask buffer, a multiple entry header buffer for storing characters of frames received by the input, and a multiple entry compare buffer for storing in an entry the results of the comparison of the characters stored in the corresponding entry in the header buffer to expected characters as masked by the mask in a corresponding entry of the expect/mask buffer. Storage into the header buffer and the compare buffer is stopped by terminating events which are detected by a state machine. A data frame recognition circuit is provided which detects a variety of data frames from among the frames transmitted over the data link to the input of the apparatus.