Writing Xenix serial I/O routine

[Steve Spear]

I've been trying to write a simple single character I/O routine for Xenix
serial ports to port a FIDO-net bbs package to Xenix.  Unfortunately I've
only been sucessfull with writing out the port - I never see anything come
back.  I open the modem line with open( "/dev/tty1A", O_RDWR | O_NDELAY )
and the handle comes back just fine.  Then I set the line settings with IOCTL
and do a write( handle, "ATZ\r", 4 ).  I see the data go out the port on the
data scope and the modem flashes and returns OK on the data scope, but when
I do a read( handle, &ch, 1 ) I never get anything.  Does someone have a small
sample program I could look at to get this working?  

Also just out of curiosity what do the devices /dev/ttyp0 - /dev/ttyp7 do?

Any help would be greatly appreciated.