Ronny,
Thanks! I am having exactly the same problem.
I am attempting to get PPPD running but I have not been able to get the
ttyS to dial using pppd settings, have not been able get the login
prompt from the connection. I am using 3104 AND the quad version (DHU?)
- now under 1.1a or 1.2 I was able to get a login prompt, dial out, and
get remote terminal session going.  Not yet under 1.3.2G.

Thanks for posting my same scenario, same problem!  I am stumped!
I keep saying mumble grumble groan and complain to keep from swearing!
Sheez!!
thanks!!
bob

Ronny Svedman wrote:
> 
> here goes:
> 
> I haven't been able to get anything at all out of the serial ports on the
> vax :(. I enabled the lines in /etc/ttys, i have created the devices for
> them (ttyS0 -S8), and i see the 8 getty:s running in ps and top. The
> system finds the mux at boot, saying:
> 
> dhu0 at uba0 csr 160440 vec 300 ipl 17
> dhu0: rom(1) version 2 rom(0) version 2
> 
> What are these numbers, and what may i look for ? is any of these numbers
> supposed to be unique (like irq:s in a PC or so), and does this appear
> normal ?
> 
> there is no error messages during selftests, and the machine has been
> running stable, except for panic during fsck problems during automatic
> boot, which is probably depending on the kernels old virtual memory
> management, (or atleast so i have been told).
> 
> Is the M3104 supported in the 1.3.2 generic kernel, or do i need to change
> ? what else can cause this deadness? if i disable the getty:s and try to
> cat things at the ports (as root) it hangs until i press ctrl-C.
> 
> I have tried with both crossed and straight cables, three-wire and DEC
> original (25 f to 25 f, known to work between a vt320 and a DECserver
> 200), and at different speeds (all in the vt320 setup).
> 
> Please, advice me of what more to try, and excuse the long explanations =)
>
-- 
real address is shsrms at erols dot com
The Herbal Gypsy and the Tinker.