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

Paul Koning paulkoning at
Fri Jun 19 07:03:31 CDT 2020

> On Jun 19, 2020, at 6:07 AM, Peter Coghlan via cctalk <cctalk at> wrote:
>> ...
> 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.

The interfaces should all work about the same, for short cables.  RS232 isn't rated as high as the others but if you're just running a 6 foot cable across the bench that isn't much of a problem.

Interesting that DDCMP is rated lower.  I wonder why that would be.  If the device handles the data CRC, the software would do the header CRC but that is easy.

I'd expect 9600 or so for BISYNC.  I forgot how CRC works -- are the escape characters in BISYNC included in the CRC, or not?  If not then you're probably looking at software CRC.  Still, 9600 baud with software CRC is doable for a J-11, so it should be for a MicroVAX as well.


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