Userland access to modem control lines?

[Danny Braniss]

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> Hi,
> Does anyone know of a way to manipulate the modem control lines from userla=
> nd?
> SVR4 has termiox and friends but I can't see an equivalent for FreeBSD.
> 
> The reason I ask is I am trying to talk to an RS485 bus - it is half duplex=
> =20
> and the protocol converter uses RTS to control the data direction.
> 
> I have a kernel driver which handles this but it has it's limitations (eg=20
> takes over the port and boot up, only usable on certain devices).
> 
> I'm going to make it a line discipline eventually, but this was a stepping=
> =20
> stone.
> 

see /usr/include/sys/ttycom.h and
 TIOCMBIS, TIOCMBIC, TIOCMGET

danny