Didn't it allow DECnet/DOS over serial lines, too? Warner Losh via cctalk <[email protected]> schrieb am Do., 9. Okt. 2025, 22:17:
> On Thu, Oct 9, 2025 at 12:32 PM Nigel Johnson Ham via cctalk < > [email protected]> wrote: > > > On 2025-10-09 13:34, Paul Koning via cctalk wrote: > > > I was poking around eBay and up came a listing for a DEC "mini > > exchange", DFMSA. What is that? The name doesn't sound familiar. It > > looks like a box with a bunch of DB25 connectors on the back, but that > > doesn't help much. > > > > > > paul > > > > > I had one once. AFAIR it is just a serial switch to access different > > peripherals from one port on the CPU. Possibly switchable by control > > sequences. That was 35 years ago though so I am not sure of setails! > > > > > http://www.bitsavers.org/pdf/dec/rainbow/ms-dos/AA-DY84A-XV_Rainbow_Using_the_Mini-Exchange_Oct84.pdf > tells how to use it with a DEC Rainbow. So all the ports are RS-232. It > was used to share Printers and modems to the Rainbow (though modems had > weird restrictions iirc). I don't know if the protocol has been > reverse-engineered (likely it has), but the MS DOS 2.11 programs are small. > > Warner >
