00446 a2200157 4500 0810451263 004.6 HEL 2942 3629 Held, Gilbert Data communication components characteristics, operation, applications New Jersey Hayden book company 1979 1979 xii, 267p. 24cm. INTERFACING AND COMMUNICATIONS COMPUTER SCIENCE L 31982 31982 0 0 0 0 LEN MAIN MAIN LEN 2008-08-11 0 004.6HEL 24680 2017-08-23 00:00:00 0.00 2016-10-31 L