I would say you ave a fault in your ibus circuit - carefully check all the RS232 Tx lines.


Sounds like Rx is working fine but Tx is missing

You can check you interface is OK as follows:
1. Plug your ibus interface to your PC on your PC desk
2. give the interface 12V and ground, leave ibus wire disconnected
3. Start and run NavCoder, try a scan.

If the interface is working correctly, you will get all your Tx messages being listed in the NavCoder display.

This is because the Tx msg goes out the com port to the interface, then onto the ibus wire, where it is then detected by the Rx line and sent back to the PC


>> Also the circuit only works when the +12v and the I-bus are connected, when the -gnd is connected the NavCoder goes into sleep mode (after 60 secs).

Definitely an interface problem!