how to make a "Break com"


i need to make a breakcom routine but it doesn’t seem to work well.
how do i do this?
i’ve red that you should send a Null char for 2 miliseconds on a baud of 4800
or something but i don’t know how to put this in a program for the jackrabbit
the one i have now doesn’t do what it should.

i have a device on the serial port that can lose sync, with a break com it wil resync again, but my break com doesn’t work well.
if i take the device from the serial port and put it back it works well again cause its sync again

thx in advance