RTS/CTS control in SCO SysV

[Clay Jackson]

I have a device that I need to talk to via a C program from SCO Unix
Sys V - the device outputs data on a serial line, and expects to see
the RTS (or CTS) line change state from high to low before it transmits.
The line should change state again to shut the device up.

Can anyone point me at the IOCTLs I need to use to control either 
(or both) of these lines?

Thanks!

Clay Jackson