ISDN  Clearly Explaine, 2nd. Ed. 
Ed Tittel...,[et. al.] 
 - [2nd. Edition] 
 - Boston, USA  AP Professional  1997 
 - xxi,422p.  24 cm 
<br/><br/><label>ISBN: </label>0126914125 
<br/><br/><label>LCCN: </label>9718892 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Integrated Services Digital Networks