how to send a break signal by uart,liux?

Hi everybody,i am working with serial port in linux. I don't know how to
send a break signal with uart. example: send a break signal 100us 
http://www.dmx512-online.com/packt.html
I am using FriendlyARM tiny6410..!
please,help me...Thanks..!

Did you ask Google first? I did.

http://www.lafn.org/~dave/linux/Serial-Programming-HOWTO.txt