Antonio Carlini <arcarlini(a)iee.org> wrote: I know, I have one, and I used it for my Inet connection when I lived in Dallas and had a 64 kbit/s DDS line. It's rated for up to 256 kbit/s with one channel active or 64 kbit/s with both channels active. Do you have any more details about DSV11 operation above the rated 256 kbit/s? What exactly is the real limit and what are the limiting factors? I have the technical description (EK-DSV11-TD), but it isn't absolutely clear. I'm not using a VAX 7000 (and don't consider it a real VAX thanks to LSB and whatever else they broke in NVAX+ when they fit it into an Alpha pinout), but I'm curious why. I mean, how is DSB32 special? I recently searched for DSB32 on Google and came upon a posting by you saying the same thing, there you also said it had something to do with the way its firmware locked memory. What exactly is wrong with it? Does it strictly follow the VAXBI spec or was it given an exception? Does it use IRCI/UWMCI pairs exactly as the spec says or is it broken? Or is the VAX 7000 kludge the one at fault here in that the memory is not presented to VAXBI as prescribed by chapter 8 of the VAXBI spec (the Must Respond Set for Memory Slave), and DSB32 just happens to be the only device that uses everything that the spec says is allowed? Or will all VAXBI devices that use BVP (interlocked queues) not work on VAX 7000 because its VAXBI interface to memory (through XMI and LSB) does not support IRCI and UWMCI? That would be DSB32, AIE/AIO (DEBNx TK50/TK70/Ethernet), all BI-to-CI adapters, DWBUA if some UNIBUS device accesses memory with DATIP-DATO (which turn into IRCI/UWMCI), what else? You said DMB32 should work, I guess it isn't using interlocked queues. But then again IRCI and UWMCI are the in the Must Respond Set for memory nodes (section 8.2.2), so it would just mean that VAX 7000 is not a real VAX as I've been saying all along. Well, neither Alpha nor DECnis firmware run 4.3BSD-Quasijarus, so those are not my options (I love my 4.3BSD-Quasijarus based router and won't give it up), but there is one more option: build a new sync serial card! We can even build both Q22-bus and VAXBI versions. MS