Smith, Sydney F <br/><br/>
Telephony and telegraphy : an introduction to instruments and switching systems. (3rd ed.) 

 - 3d ed. 
 - Oxford :  Oxford University Press  1978. 
 - xiv, 278 p. : ill. 
<br/><br/><label>ISBN: </label>0198593589 0198593570 
<br/><br/><label>Subjects--Topical Terms: </label><br/>TELEGRAPH<br/>TELEPHONE
<br/><br/><label>LC Class. No.: </label>TK 6161 Smi