There might be manual for this DC source so read SCPI commands from there.
I assume that minicom sends line-feed character after each enter
you press, but SCPI requires \n
for command separator. Hence the Minicom does not work.
However you can just echo commands to serial port from bash command line.
Setup serial port
stty -F /dev/ttyS0 raw speed 9600 -cstopb cs8 -ixon
Echo commands to /dev/ttyS0
echo -en '*RST\n' > /dev/ttyS0
Notice: I'm assuming your device is connected to /dev/ttyS0
.