Welcome to the Marine Electronics Forums presented by Panbo and SeaBits.
Heads up for Recent ICOM M605 Purchasers
I bought an ICOM M605 in early April 2019 (serial # 11002439) and the DSC position reporting functionality didn't work (report and report request, receive and transmit). ICOM support confirmed it was disabled by default. Since this is US-only functionality, I'm guessing they forgot to change the defaults when they ran a US batch. ICOM support said any dealer capable of reprogramming the radio can change the defaults. Mine was done for free.
My M605 now outputs the information via NMEA2000 to allow my chartplotter to put a symbol on the chart when a DCS position report is received.
My former Beneteau's ICOM M-422 radio also had it disabled, which was really frustrating when I was first testing it our with Ben during a visit to Maine.
In addition to providing an MMSI number, enabling the M-422 to receive DSC calls required two configuration changes, both could be done by any user, but you needed to know it was disabled to even begin to think you needed to go through the tiny print in the manual and enable it. It also required you had someone to test with, to know there was a second setting to change.
Other than a test, I have never had anyone answer a DSC call from me, or receive a call.