Herb Peyerl <hpeyerl@beer.org> wrote:
> When we first got 400's, we tried the fanouts and they didn't work. I even
> remember asking an Apollo tech person and they answered in the negative. Also
,
> looking on the motherboard, there is only one UART and it's a 16550 so 
> unless they buried the other 3 UARTs inside one of their ASIC's, I don't
> see how this is possible.  (And if they were going to bury 3 UARTs in an
> ASIC, then why not the fourth?)

The expansion cable did appearently work on the 400's in both domain and
hpux boot modes. There is a HP support document that deals with the 400 
serial port (and includes a pinout). I'm not sure of the legality of 
redistributing it, but the url is 
   http://support.mayfield.hp.com/kdb-bin/wwwsdoc.pl?DOCID=CSCI00000259

Basically, the first serial port is connected to the 16550 and the other
two to the infamous utility chip under hpux, while under the domain 
boot mode, all three are connected to the utility chip.

Andy Carey                                                careya@peak.org