11
Subscriber stage
Text Box: To ETC
To  ETC
ETC: Exchange terminal circuit
Speech store: shift registers storing bits for time switching
Control store: gates guiding speech store switches
Connects to: digit receivers, info tones, test equipment
Control System: subscriber
                           authentication, routing, billing, O & M, ...
Concentrator
internet access (DSLAM)
centrex service
MUX