Cancel respawn getty on serial tty

[Rod Nussbaumer]

I have a setup that uses busybox as the init process. It works fine, and
is configured to spawn/respawn a getty on ttyS0. Sometimes, however, I
would prefer to cancel the getty process on the serial port, in order to
use the serial port for other purposes, such as setting up a C-kermit 
connection on the port. Ideally, I'd like to then restart the getty 
respawning when I'm done with the port.

How can I do this without modifying inittab and rebooting?
Thanks.
    ----   rod.