recently, they bought a new cash drawer, connected through COM port.
according to the manual that came with it,

To open the drawer through COM1 under QBASIC:

OPEN "COM1:300,N,8,1"
FOR RANDOM AS #1
PRINT #1,"0000000000"

any idea how to convert it into fasm like?

problem solved.
coded using vb

open "COM1" for write access as #1
print #1,"0000000000"
close #1

:p

Or you can use OllyDbg for Windows to dis-asm it, like most people (including me) do to figure stuff like that out. It should give you what u need if u can find the right code.

Don't you people ever read the docs? The com port is very simple to use in assembly. Just open a handle (CreateFile) and write/read data (WriteFile/ReadFile).

edit: Although it would be faster to read the appropriate docs than to find some program and reverse it, on reflection, I can see that it may not be so much fun.