Telephone Relay Rack

A rack, part of a telephone central office, on which the relays and elements of various telephone central office circuits such as trunk and line circuits, and miscellaneous testing and alarm circuits are mounted. The rack is stocked as a completely wired and equipped unit. Excludes items on which strowger or stepping switches are mounted. Do not use if a more specific item name can be found in this index. See also shelf, telephone switch; and relay assembly.