HOW DO I UNBLOCK A SERIAL LINE ON SUN3?

[charles at sifvx6.sinet.slb.com]

I have a problem on a SUN3/60 OS3.5 serial link from /dev/ttya to a plotter
which uses XON/XOFF for flow control. If someone cycles the plotter power in
mid-plot (eg to unblock the paper feed), the serial line hangs because the SUN
is waiting for XON (^Q) and the plotter is not clever enough to send XON when
power is restored. I use the following script to send files...

	(stty -even;stty -odd;stty -echo;cat $1) > /dev/ttya

where $1 is the file name. If I kill the process, it does not unblock the
serial line. If I do a 

	kill -1 1

it does not clear the buffer. Nothing works except reboot or disconnect
/dev/ttya and reconnect to a terminal and type SPACE,RETURN or ^Q, which
empties the buffer onto the screen. Any ideas on clearing the buffer from the
SUN end or improving the script would be much appreciated.