Telephony : a detailed exposition of the telephone exchange systems of the British oost office
v.1. ; ill.
. - (Telephony ;vol. 2 )
Includes index
Content notes : V.1.General principles and manual exchange systems
Telecommunication.
v.1. ; ill.
. - (Telephony ;vol. 2 )
Includes index
Content notes : V.1.General principles and manual exchange systems
Telecommunication.