Helmers, Scott A.,   1951- <br/><br/>
Data communications :  a beginner's guide to concepts and technology /  [Book]. 
Scott A. Helmers.  
 - Englewood Cliffs, N.J. :   Prentice Hall,   1989. 
 - xvii, 302 p. :   ill. ;   24 cm. 
<br/><br/> Includes index. 
<br/><br/>Bibliography: p. 277-282. 
<br/><br/><label>ISBN: </label>0131988700 
<br/><br/><label>LCCN: </label>88032431 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Computer networks.<br/>Data transmission systems.