Comm Port Send and Receive

[Camm29]

Hi ,

Still having with problems Comm Port sending and receiving.

Before i can write to the some Hardware i must wait for the character ">"

i have tried 

write Data to file COM1:
wait 250 milliseconds
read from file COM1: until ">"
X
X do something with the received Data
X
then write Data to file COM1:

or 

write Data to file COM1:
wait 250 millieseconds
read from file COM1: until empty
if the last char of it =">" then
X
X do something with the received Data
X
write Data to file COM1:
etc etc.....

If i loop it sometimes writes before a ">" is received 
???????? 
It does not seems to check for ">" or misses ">" completly
The Hardware always sends ">" when ready !

Help Help 

Camm