Synchronous serial Re: E-Mail Formats RE: Future of cctalk/cctech

Peter Coghlan cctalk at
Fri Jun 19 05:07:23 CDT 2020

Antonio Carlini wrote:
> On 18/06/2020 14:06, Peter Coghlan via cctalk wrote:
> >
> > I have found the whole thing very confusing too.  My suspicion was also
> > that they were pretty much the same thing but the DST32 had exernal
> > connectors suitable for mounting in a MicroVAX 2000 while the DST32 had
> > external connectors that could be mounted in a MicroVAX 3100. That is,
> > until I also came across the preliminary version of EK-283AA-AD-001
> > which threw cold water on that theory.  Unless it was originally called
> > the DSH32 and then renamed to DST32 for the MicroVAX 2000 or something...
> I expect that the uVAX 2000 interface was around well before the uVAX 
> 3100 one. I suspect that the docs was wrong or that something got 
> renamed at some stage. If I ever frind my notebooks from the time I can 
> take a look.

I'd be very interested to know what the story was if you manage to locate
those notebooks.

> >
> > I was hoping to use VAX WANDD but I ended up having to install DECnet OSI
> > on VMS 7.3.  Perhaps if I dig up an earlier VMS version, I can avoid 
> > using
> > DECnet OSI?
> If you further along it got renamed to DECnet-Plus ... would that help :-)
> I don't know when Phase IV support stopped for WANDD. DECnet-VAX 
> Extensions went out in the V5.4-3 timeframe IIRC. Certainly for a while 
> you have a choice and were not required to run DECnet/OSI. In fact the 
> only reason that DECnet-VAX Extensions shipped was (iirc) that PSI/WANDD 
> was ready and DECnet/OSI wasn't.
> Anyway, pre VMS V6.0 I'm sure you can just pull the latest contemporary 
> WANDD kit off a VMS CD and you'll be fine.

I already tried extracting ZSDRIVER.EXE from the DECnet/OSI kit for VAX/VMS 7.3
and placing it in SYS$LOADABLE_IMAGES but ZSA0: remained stubbornly offline
until I installed the rest of DECnet/OSI and the LES$ACP_V30 process started.
I think I have an old CD containing a WANDD kit somewhere but I can't seem to
put a hand on it right now.  I probably put it in a "safe place" :-(

I was pleased to find that I have a grey DEC folder containing AA-LN26B-TE VAX
WAN Device Drivers Installation Guide, Specifications and Programmer's Guide
for VAX/VMS 5.0  Software Version: VAX Wide Area Network Device Drivers V1.1
First Printing July 1988  Revised, January 1989.  I'd forgotten I had these!

These manuals mention the DSV11 and DST32 but there is no reference to the
DSH32 anywhere.  The installation guide says the device driver for the DST32
is ZSDRIVER.EXE so this seems to suggest that the DST32 and DSH32 are the
same thing or at least very similar.  Maybe there was a difference of opinion
between the hardware people and the software people as to what it should be
called :-)

The specifications manual says: "The DST32 is a single line interface for
single board VAX systems. It provides RS-232-C, RS-442-A and RS-423-A
connections to dial-up or leased synchronous communications lines and
operates in both character-oriented and bit-stuffing mode.

> On the synch side the idea was to get away from having a set of (often 
> different) cables for each interface. Instead everything had the same 
> 50-pin connector and then you picked the appropriate cable for V.25 or 
> X.21 or whatever you needed. My DST32 has such a connector, as does your 
> DSH32. I expect that the DSV-11 also is the same. DECnis certainly is.
> >
> > and I also have two Nokia DS 60100 baseband modems, one with a V.35
> > interface card and one with an X.21 interface card.  When I hook up the
> > former with the BC19F cable, I can get the lights on the modem to react
> > when I try to access ZSA0: on the MicroVAX.  However, I can't get any
> > reaction when I use the BC19C cable with the latter even when I jumper
> > the modem to take account of the fewer signals available in X.21. It
> > may be that the BC19C is meant for something other than the DSH/T32...
> I don't remember the cable part numbers (although they will be in the 
> manuals) but if it plugs into the 50-pin connector then it should work.

I found details about many of the interface cables, including wiring diagrams
in EK-DRT90-OM DEC WANrouter 90 Owner's Manual on the web and more stuff
in EK-A0497-IN DEC WANserver 150 Installation/Owner's Guide.

> > Anyway, this whole line of attack is fairly academic as the modems can
> > only do 48kbps - 160kbps and the maximum for the DSH/T32 seems to be
> > 19200bps.
> >
> I'd be surprised if they don't work at up to 56k at least. Maybe not 64k 
> (I remember the DSV11 firmware engineer telling my that some extra work 
> had to be done to get one of the DSV11 modes to work properly at 64k 
> even in pathological cases, so maybe other, lower-end interfaces didn't 
> get the same love).
> Above 64k would not have been a normal use case back in the day - I 
> don't have any data handy to check what should work though.

The specifications manual says that the maximum speed for the DST32 is
19200 bps (for HDLC or SDLC) or 9600 bps (for DDCMP) but worryingly
doesn't list a speed for BISYNC which is what I want to do with it :-(

It also says the supported line interfaces for the DST32 are:
RS-232-C/V.24/V.28, RS-423-A/V.10/RS-449 and RS-422-A/V.11/RS-449 but not
V.35 which seems strange because the only reaction I have got from it so
far is using the V.35 interface cable.  At least it suggests it should work
with the V.24 cables when once I manage to come up with a suitable clock.


> Antonio
> -- 
> Antonio Carlini
> antonio at

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