Sorry I was not following this thread. I have tons of emails everyday and little time to spend on the forums.
First Question always is; What are you getting back in the Rx buffer. Until you get only FF during communications idle, then none of the operations with the EASunlock software will work.
If you get FF and 1 in the Rx buffer, you are on the wrong comm port. (You are on a internal laptop loopback port)
If you get nothing back in the Rx buffer during communications idle, then your USB 2 Serial adapter is not working or your cable is wrong, or the Range Rover wiring is suspect. (No communications at all; Tx and Rx are bad)
If you get 28 or 80 back in the Rx buffer then your USB 2 Serial adapter might stil be acting up, or your cable might be incorrect, or the Range Rover wiring might be suspect or the EAS delay relay might be suspect. (Some communications; Tx and Rx are working; EAS power reset is not working)
Overall, make sure you have drivers installed for the USB 2 Serial adapter. Make sure you have the windows device manager open when you plug the USB to serial adapter in. Watch the new comm port appear in the windows device manager. When the comm port appears use that inside the EASunlock software configuration for the comm port number. You can also shift the comm port number that the USB 2 serial adapter emulates. Changing the enulated serial port can sometimes also cause the adapter to suddenly start working.
Make sure the cable is correct. I think the cable is the most likely cause of the lack of communications. You have tried a laptop with a built in RS232 so that is uaually a good working test. But that failed. I think your cable is bad and then next I would inspect the OBDII port wiring harness by droping the footwell pannel. Then I would inspect the EAS ECU C117 Wiring harness for damage.
Wiring harnesses in the Range Rover can go bad. I usually ask if the heater core has ever leaked. If you have had a coolant leak in the heater core, then the OBDII port and some of the wiring harnesses that are next to the heater core are suspect. But check the OBDII port first it is easy to get to and can be cleaned with some contact cleaner.
Next I inspect the EAS ECU. The EAS ECU is located under the Left hand seat. Some pannels will need to be removed and you will also need a medium sized phillips screwdriver with a very very short handle. The EAS ECU is located on the bottom. Use a flat head screw driver to pop the EAS C117 multiplug connector off. Inspect the wiring harness and the C117 pins. If the connector has ever been opened, make sure that the plastic retaining combs are still on either side of the C117 connector. The plastic retaining combs keep the pins in contact with the EAS pins. Some souorces also say that the rubber gasket on the C117 connector is too thick and prevents the connector from seating correctly with the EAS computer. So try removing the rubber gasket for testing. Long term, you can remove about 1/3 of the thickness of the gasket with sand paper and refit.
Also inspect the EAS delay relay. The EAS delay relay is located under the left hand seat on the outer side of the seat. It is a black tall rectangular relay, which has its own wire harness and is attached to the seat subframe with a rubber groumet. Make sure that the wires are in good shape. The EAS is power cycled during the EAS communications protocol. If you can not hear or feel the EAS delay relay clicking when you press "initialize", then it might be bad. Try replacing it.
Can anyone sticky this thread answer? I do not want to type it all again.