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

Ethan Dicks ethan.dicks at
Thu Jun 18 13:55:13 CDT 2020

On Thu, Jun 18, 2020 at 2:48 PM Paul Koning via cctalk
<cctalk at> wrote:
> > On Jun 18, 2020, at 2:14 PM, Peter Coghlan via cctalk <cctalk at> wrote:
> > As I mentioned in another reply, I have a pair of baseband synchronous modems
> > and were it not for a speed incompatibility between them and the MicroVAX
> > synchronous serial interfaces I have access to, ...
> I'm curious about that.  Synchronous modems supply the bit clock to the interface.  So a synchronous interface works at whatever speed the modem delivers, so long as it's not too fast for the interface. What are the Microvax sync interfaces you have?  DMV?  DUV?  A DMV will work at up to 56 kbps.

We used to run our sync serial stuff between 9600 and 56kbps, both our
own Bisync products, and DDCMP over interfaces like the one that's
part of the DMF32.  We had customers in Europe running our products at
64kbps with no problems, and we did have one modem eliminator clocked
at 115kbps for testing, which is the max speed for V.24, IIRC.

56kbps should be safe for the devices you are describing, but it might
go a little faster.


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