Off-page connectors maintain the continuity of lines that span drawings.
They are used in pairs: in the originating drawing and in the connected drawing. A line leaving a drawing requires a To connector. The same line in the second drawing requires a From connector. Both are represented by the same symbol and both have the same connector number to identify the continuity.
You can tell at a glance whether a connector is disconnected, connected, or connected but with mismatched properties. The appropriate status icon appears next to the connector: 
Note: Only a connector that is attached to an SLINE has a status icon.
Keep in mind the following:
- If you right-click a connector and click Properties, you can enter the Connector Number (10115 for example) and Origin or Destination (FROM T - 100 and TO E - 200), for example).
- The drawing number, unlike the connector number, is a drawing property. If you right-click the drawing name in the Project Manager and click Properties, you can enter a DWG Number. The appropriate Connected TO and Connected FROM Drawing Numbers are then displayed automatically within the connector when the connection is made.
- You can connect an unassigned line OPC to and assigned line OPC but not the reverse.