GE machines often have multiple serial ports. Only one of these will communicate with Monitor. These are all 9 pin male connectors. There may be other serial ports on the side of the machine for communication with the ventilator. There is currently no Monitor module for these ports.
The connectors are on the back of the module box, and labelled X8.
You may have to remove a plastic panel from the back of the Aisys to get to this port.
On Aestiva machines there may be a metal panel covering the back of the shelves housing the box. You can either remove this panel, or pull the box forward to plug the cable in.