How do I connect to TTY/COM (/dev/ttyUSB0)?

Use one of screen's lesser known features:

screen /dev/ttyUSB0

busybox microcom -t 5000 /dev/ttyUSB0

Source: http://forum.xda-developers.com/showthread.php?t=1471241

you can use ckermit also. It should be in the repository. After installing it create a file in your home directory called .mykermrc then add the 5 following lines:

set line /dev/ttyUSB0   
set flow-control none  
set carrier-watch off  
set speed 115200  
connect 

parameters can be adjusted as necessary.
save the file.
to start it

sudo kermit