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Security of the Green and Federal Telephone Systems. Note by Secy. Circulating Letter from Director of Naval Intelligence

1940

ANNEX C. Security of Green and Federal Telephone systems. All users of Green or Federal line telephones are reminded that these systems are NOT secret. 2. Inside calls in a building on the Green system are more secret than the black system in that the two are not inter-connected and that operators for the Green exchange are especially selected. Outside Government buildings the Green system is in a number of cases connected to ordinary exchanges and is therefore little more secure than the ordinary system; further there is always danger of overhearing owing to faults and contacts.
security second world war leakage of information joint intelligence sub-committee chiefs of staff british domestic security telephone communications c edwards
Collection ID
CAB81
Conflict
Second World War
Document Reference
CAB 81/99/37
Document Types
Memorandum
File Reference
CAB 81/99
Identifier
10.1080/swwf.cab81.0099.037
Keywords
Security Telephone Communications Leakage Of Information
Languages
English
Organizations
Chiefs of Staff Joint Intelligence Sub-Committee
Pages
3
Persons Discussed
C Edwards
Published in
United Kingdom
Series
War Cabinet. Joint Intelligence Sub-Committee. Memoranda. 4th December 1940 - 15th January 1941. Papers Numbers. JIC (40) 395-436 & (41) 1-22. Volume IX
Themes
British Domestic Security