Telephony class : A Course
Curso telefonia básica / Cláudio Romano
Ergänzungen: beschreibung der in der reichs=telegraphenverwaltung gebräuchlichen apparate
Telephones: their construction, installation, wiring, operation, and maintenance : A practical reference book and guide for electricians, wiremen, engineers, contractors, architects, and others interested in standard telephone practice / W. H. Radcliffe, H. C. Cushing