NCR data communications concepts / 
by the Technical Publications Department of NCR Corporation. 
 - Carmel, Ind:  Sams,  1971. 
 - 224 p. :  ill. ;  22 cm. 
 - Blacksburg continuing education series. .
<br/><br/><label>ISBN: </label>0672215470 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Data transmission systems.<br/>Telecommunication.