screen /dev/ttyACM0 115200

sudo stty -F /dev/ttyACM* 115200 -parenb -parodd -cmspar cs8 -hupcl -cstopb cread clocal -crtscts
-ignbrk brkint ignpar -parmrk -inpck -istrip -inlcr -igncr -icrnl ixon -ixoff -iuclc
-ixany -imaxbel -iutf8
-opost -olcuc -ocrnl -onlcr -onocr -onlret -ofill -ofdel nl0 cr0 tab0 bs0 vt0 ff0
-isig -icanon iexten -echo echoe echok -echonl -noflsh -xcase -tostop -echoprt echoctl
echoke -flusho -extproc

$ cu -l /dev/ttyACM0 -s 115200
<continuous stream of data>
$ killall cu             # (from another shell)
$ cat /dev/ttyACM0 | hexdump -c
<e.g. 7 bytes>
$