DCS interface to MFD

[HiViet]

Hello Chuck
I have the same issue with my VHF 240 to GPM400. The radio does not tx DSC message to MDF. My VHF 240 connected to port 2 NMEA of the GPM400 at 4800 Baud rate. The radio received GPS position from MDF, but I dont know if the radio tx any DSC signal to the MDF.
I tested the position request with my friends at the marina. The Radio received the position request, but it did not display anything to the MDF. I monitored NMEA port 2 RX side on the GPM400, I didnt see any DSE/DSC message.

Does the radio has to be connected to port 1 of the MDF? or it be connected via port 2?

Thank you Chuck

Viet