Held, Gilbert,  1943- <br/><br/>
Understanding data communications :   from fundamentals to networking / 
Gilbert Held 
 - New York:   J. Wiley & Sons,   1991 
 - xviii, 546 p.:   ill.;   25 cm. 
<br/><br/> Includes index 
<br/><br/><label>ISBN: </label>0471930512 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Data transmission systems<br/>Computer networks