Title
Telephone Four Frequency Signalling System
Reference
UK0108 NAEST 006
Date
1930
Scope and Content
Assembly drawing and 8 photostatic copies of schematic drawings for an experimental 4-frequency signalling system for long distance direct dialling., the forerunner of Subscriber Trunk Dialling (STD) being developed by the International Standard Electric Corporation at their Development and Research Laboratories, Hendon in 1930. These drawings are specifically for a London-Leeds link.
Exent
9 drawings
Language
English.
Persons keyword
International Standard Electric Corporation
Subject
Telephone equipment, Telephone signalling equipment, London, Leeds, Subscriber Trunk Dialling, Hendon
Conditions governing access
Open
Level of description
sub-fonds