Held, Gilbert. Understanding data communications : from fundamentals to networking / Gilbert Held. - Chichester :;New York : Wiley, 2000 - xvi, 852 p. : ill., map 26 cm. Includes index. ISBN: 0471627453 (alk. paper); 9780470841488 LCCN: 32094 Subjects--Topical Terms: Data transmission systems.;Computer networks. LC Class. No.: TK5105 / .H429 2000 Dewey Class. No.: 4.6 / HEU 2003