Abstract: A method of transferring data from an ATM (asynchronous transfer mode) physical device to an application specific circuit (ASIC) comprised of receiving a continuous stream of ATM cells from the ATM physical device, identifying a virtual circuit from a header of each cell, providing an identification (address) of the virtual circuit to an output for reception by the ASIC, providing a continuous stream of payload contents of each cell received from the ATM physical device directly to an output for reception by the ASIC, calculating a cyclic redundancy check (CRC) on data carried by cells forming each packet for each to virtual circuit address and providing an indication to the ASIC of invalid data relating to a packet having a particular virtual circuit in the event the CRC is indicative that data in a packet is incorrect.

Abstract: A method of converting a variable bit rate of a transmitted sequence of cells having F cells per frame and a peak cell transmission rate P into an effective peak rate of transmitted cells for each frame. The steps include determining a number of ghost cells for each frame which when added to the actual number of cells in each such frame produce a peak rate of cells for that frame and transmitting in cells of a subsequent frame a number corresponding to the number of ghost cells determined for the preceding frame.

Abstract: A frame word in a word-interleaved multiplexed serial data stream is detected by latching a word from the data stream and comparing it with the frame word. If there is a match, latching of consecutive words continues for at least one frame to check for the frame word in the next frame. If the compared words do not match, then a bit slip is effected so that the next word latched and compared has a different bit orientation from the preceding word, whereby in one frame words with various different bit orientations are examined for the presence of the frame word, and all possible bit orientations of the words are checked over a number of frames. The arrangement eliminates the need for one counter in the frame find circuit and simplifies its control circuitry.