Smith, Sydney F. <br/><br/>
Telephony and telegraphy A :  an introduction to instruments and exchanges (step-by-step and common control) / 
by Sydney F. Smith. 
 - 2nd ed. 
 - London :  Oxford University Press,  1974. 
 - xv, 282 p. :  ill. 
<br/><br/><label>ISBN: </label>0198593465 
<br/><br/><label>Subjects--Topical Terms: </label><br/>Communication engineering.<br/>Telecommunication systems.<br/>Telephone sysytems.<br/>Telegraph.