Sparc classic serial ports ttya vs cuaa

Hi all,

I've been working on getting gpsd working on one of my old Sun IPXes but 
I've run into a problem with ldattach needing the /dev/cuaa device.  The 
serial port /dev/ttya is working with gpsd directly but ldattach 
requires /dev/cuaa.  However, according to the system logs, ldattach 
issues the error (ldattach is run as root):

ldattach: can't open /dev/cuaa: Device not configured

However, the device does exist in the /dev tree:

# ls -l /dev/cuaa 

crw-rw----  1 uucp  dialer   12, 128 Feb 21 18:52 /dev/cuaa

THe matching tty also exists

# ls -l /dev/ttya
crw-rw----  1 uucp  dialer   12,   0 Feb 21 18:52 /dev/ttya

I'm at a loss to understand what's going on.

Straight use of /dev/ttya and gpsd works fine, gpsd is able to detect 
the GPS receiver plugged into the port.  However, I need ldattach for 
the PPS discipline that I'm feeding through the DCD line.

The system is being booted with a keyboard and display plugged in so, as 
far as I know, no gettys are attaching to the serial ports.

Thanks