sentences:  In a Terminating Marker, there was also a cross-connect field which was used to declare which frames the marker had to access in order to complete the call to the desired line.Subscriber lines were terminated in arbitrary locations on the Line Link frame, and it was the task of the Terminating Marker to locate the line, and close the required crosspoints to connect it to the call waiting on an incoming trunk.When one office was constructed, retired, or changed, staff in other offices received a "Routing Letter", ordering the cross connect fields to be changed at a particular date and time, usually after midnight, to accommodate the change in the network.