Held, Gilbert <br/><br/>
Understanding data communications 
Gilbert Held. 
 - 7th ed.. 
 - Delhi  Pearson Education  2002 
 - xv, 765p.; 24cm. 
<br/><br/><label>ISBN: </label>8129702118 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Data transmission systems.
<br/><br/><label>Dewey Class. No.: </label>005.71  / H52U