... Just a fun note; when I did POS (packet_over_sonet) that most high_speed internet links 10G and 40Gbit is using today, I basically copied DDCMP minus the retransmission of broken packets part. It's byte_syncrounous.. -:) (As we could not fit the HDLC bit_stuffing in the FPGA of 1995 at OC3/STM1 (155Mbit) speed.) -P