Hi Hugh,
Not sure exactly what you're doing, why you need to draw straight connectors in space. Usually connectors are used to connect shapes together.
Anyway, here's some options:
1. Use the Line tool to create your lines
2. Hold down the Shift key when using the Connector tool. This will constrain the connector to horizontal, vertical and 45-degree lines.
3. Right-click the connector and choose "Straight Connector". Work with duplicates of this connector.