I'm can connect using - Serial, com3, 115200 I get this and can go no further. <iDCC++ BASE STATION FOR ARDUINO MEGA / ARDUINO MOTOR SHIELD: V-1.2.1+ / Mar 17 2020 21:15:07><N0: SERIAL> I've used every flowcontrol setting and still nothing. Next steps are?
I believe you don't need flow control with Mega's USB. Take care to properly input each and every symbol of commands you are sending. Remember, you don't have to complete commands with Enter. If the command is correctly typed in, you will get reply right afer the last '>' symbol entered.
Its a while since I tinkered with mine, but I think you may need 'local echo' on otherwise you won't see what you're sending to the base station.