On 2013-04-05 04:10, Dave McGuire wrote: On 04/04/2013 10:01 PM, Johnny Billquist wrote: Apparently not. The reason I came up with the device is that I used a PDP 11/40 with a DU11 to connect to a Burroughs B7700 using an RJE like protocol. It was called SYSTEM/SATCOM IIRC. The PDP ran RT-11 V4. Other than that, networks were built using 1200 baud modems on serial lines. No DMF32 nor DZ11 in '79. How did one connect all those VT52's and LA36's, via a DL11? I thought DZ11s were around back then. But if not, the DH11 sure was, 16 lines, DMA output. Pretty sure they had DMA input too. Nope. DMA output only. Crap, really? Yup. However, it at least have a decent input buffer, so with some good programming you don't need to have one interrupt per character, when things are getting bogged down. But that's for terminals up to 9600 baud. 19.2K. Not the original DH-11. 9600 was the highest, unless you count the external clock ability they have. Mine was a DH-11AD, and it definitely went to 19.2K. I think you need to refresh your memory... :-) http://bitsavers.trailing-edge.com/pdf/dec/unibus/EK-0DH11-MM-003_Apr75.pdf But they DH-11 is way better than a DZ-11. The only problem being (as mentioned), they were big. A whole 9-slot backplane for one controller. Yes. I had one on my 11/34a years ago; it was in an external expansion chassis. I did love that mux, though! I got one again a couple of years ago, not sure which machine I'll put it in. I think I might still have access to one stashed away, but for most of the time, I've actually used an Emulex controller that is DH-11 compatible, but a single card. (And that one actually can do 19200, but only have a little more limited modem control.) Johnny -- Johnny Billquist || "I'm on a bus || on a psychedelic trip email: bqt at softjar.se || Reading murder books pdp is alive! || tryin' to stay hip" - B. Idol