Thanks for replying.....

The com port selected within NavCoder is the same as the port associated with the usb-serial port..

I'm wondering if the i-bus connector is faulty...although this would seem somewhat unlikely, judging by the positive results from all of the other members who have tried this...also the computer 'sees' the connector, so maybe I´m clutching at straws on this one....

Any other ideas ? I'm a desperate man...

Many thanks.