sentences:  Number 1 Crossbar offices made use of complex and versatile Originating and Terminating Senders to communicate within themselves, and to other switching offices.When a subscriber lifted their phone off the hook, they were connected to an Originating (also known as a Subscriber's) Sender.This sender received and registered the dialed digits, communicated with an Originating Marker to establish the path for the call, and then pulsed the dialed digits forward to the terminating office in whatever format was required.