RS 232 communication with weighing machine

Question

hi,
i am developing an application which needs to connect to a weighjng scale throug rs 232 and capture the output.
after inserting the record however the pc needs to send the tare command to the weighing scale in order to set the scale to zero.
now he tare character as far as i guess ia T
i sent the command like this

serialport1.write(chr(27) & "T" & chr(13) & chr(10))

but there is no effect on the scale can somebody help.
its very urgent.

thanks in advance
Proganesh