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

Peter Coghlan cctalk at
Thu Jun 18 17:11:00 CDT 2020

Ethan Dicks wrote:
> On Thu, Jun 18, 2020 at 2:42 PM Peter Coghlan via cctalk
> <cctalk at> wrote:
> > Thanks for your reply Paul.  My eventual goal is to be able to use the
> > synchronous serial interface on a MicroVAX to connect to IBM machines that
> > only support bisync lines.
> I'm curious which software package you are using.  In the 80s and 90s,
> I worked for Software Results Corp, and we sold hundreds (small
> thousands?) of Unibus, Qbus, and VAXBI interfaces and software suites
> under the name COMBOARD for Bisync and SNA comms from DEC-to-IBM
> (RSTS, RSX-11, VMS, and UNIX).  In my experience, people paid us
> $10K-$25K per line because they had problems with whatever other
> solution they were looking at that cost less.  I don't know any
> specific details on where the gaps were, but just that people did
> experience bugs or missing features that made them come to us.  I'd
> like to hear about what you are encountering once you get to the point
> of passing bytes.

I am using a very old package called HUJI-NJE which implements NJE links
on VAX/VMS and UNIX.  This was later developed into "funetnje" which added
some enhancements but broke the VMS functionality.  I backported some
of the funetnje enhancements into HUJI-NJE in order to use them on VMS.
NJE over TCP/IP is implemented on both platforms but on VAX/VMS, there
is also supposed to be support for using synchronous serial interfaces in
the form of a DMF32, DMB32 or DSV32 (is that like a DSV11 I wonder?).
If this all works out, it may be possible to use it to get NJE links into
IBM mainframe hardware that only has support for bisync lines.  It might
also have applications in talking to 3270 terminals connected via bisync

HUJI-NJE is not great for debugging the hardware with so I am also using
a pair of of example programs I found in AA­PHEPB­TE DECnet/OSI for VMS
VAX WANDD Programming.

> >  However, I don't have access to any such IBM kit
> > at the moment so I have to make do with trying to get the MicroVAX to talk
> > to another instance of itself for now.
> For bisync (3780/HASP) that should be just fine.  There's a simple
> difference in the protocol so that each end can tell who is the
> master, and AFAIK, any implementation you encounter should be able to
> be set in the appropriate mode, but you _do_ have to tell each end
> what their role is or they will chatter endlessly if they both think
> they are the master.

NJE is supposed to be able to use hardware features of devices such as
the 2703 to be able to decide which end gets to be primary and which
end gets to be secondary.  Sounds like it will be fun to implement...
I think endless chatter whether idle or not seems to be a feature of

> Apologies if you already know this.  It's been a long time and I'm not
> sure who remembers what details about obscure comms from 30-40 years
> ago.  I myself haven't even set up a bisync connection in 25 years.  I
> used to do this stuff every day, then by the mid-90s, it entirely
> evaporated.

I am fairly well up on NJE but only over TCP/IP until now.  All this
synchronous serial stuff is completely new to me so I am grateful for
any and all information I can get about it.


> -ethan

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