In message <199905111501.LAA15124@guild.net>Lord Isildur writes
>
>
>This is sort of stretching it, but does anybody know if anyone has
>ever looked into (or achieved) modifying the external clock supplied
>to the 8530 serial interface in the DS5000/240? the 8530 is a very 
>fine UART, for example older macintoshes used them to drive AppleTalk
>ports at 230.4 kilobits/sec, and so it is sort of disappointing
>to see that DEC only lets them run at 38400. I dont think i know wnough
>to try to overclock the external signal myself, but does anyone here know
>if its even possible to drive it at higher speeds? 

The NetBSD drivers work fine up to 115200, as far as I can tell.  

We once had a /240 in the lab here that could send fine at 115200, but
got balky at synching to the recieve-side start bits from a Metricom
Ricochet at anything above 57600 and would receive garbage with the
top bit set, instead of what the Ricochet sent.  I haven't been able
to reproduce that since, and I'm not sure some people beleive it
really happened :).

If you put them into synch mode the hardware should work up to 230k.

>I believe that some DEC3000 workstations also had these chips in them.. 

Yup.