[Hydra move - Bell circuits]
Emergency planning, Emergency communications, EASE, landlines
Possibly a rough diagram of circuits routed between Carp, the Bell Telephone repeater, and Leitrim.
Fixed Communications - Hydra Telegraph Relay System - Relocation of Hydra - Plans and Policy, RG24, S-2723-2, Vol. 1, Library and Archives Canada (LAC)
undated
Graphic