Held, Gilbert <br/><br/>
Understanding data communications / 
revised by Gilbert Held, with contributions by Gerald Lueke and Charles W. Battle. 
 - 5th edition 
 - Indianapolis :  SAMS Pub,  c1996. 
 - xv, 504 p.: ill; 
<br/><br/> First edition by., George E. friend...=et al.= 
<br/><br/><label>Subjects--Topical Terms: </label><br/>data transmission systems