Handbook of data communications / 
UK Post Office. 
 - Manchester :  NCC,  1975. 
 - 396 p. :  ill ;  25 cm. +  hbk. 
<br/><br/>Bibliography: p. 373-374. - Includes index. 
<br/><br/><label>ISBN: </label>0850121213 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Data transmission systems--Handbooks, manuals, etc.
<br/><br/><label>Dewey Class. No.: </label>004.6