root@trb-dev:/home/mod6/fg4# stty -F /dev/ttyUSB0 115200 raw -echo -echoe -echok
root@trb-dev:/home/mod6/fg4# dd iflag=fullblock if=/dev/ttyUSB0 of=fg4.fg3.bin
^C2560218+0 records in
2560218+0 records out
1310831616 bytes (1.3 GB) copied, 172701 s, 7.6 kB/s

root@trb-dev:/home/mod6/fg4# ent fg4.fg3.bin 
Entropy = 8.000000 bits per byte.

Optimum compression would reduce the size
of this 1310831616 byte file by 0 percent.

Chi square distribution for 1310831616 samples is 243.98, and randomly
would exceed this value 50.00 percent of the times.

Arithmetic mean value of data bytes is 127.4993 (127.5 = random).
Monte Carlo value for Pi is 3.141570147 (error 0.00 percent).
Serial correlation coefficient is -0.000043 (totally uncorrelated = 0.0).
root@trb-dev:/home/mod6/fg4#