[time-nuts] Special connector for Symmetricom X72 rubidium standard

Christoph Kopetzky ck at cksd.de
Fri Aug 18 07:50:20 EDT 2017

Hello all,

here is the connection schematics from symmetricoms designer manual for 
the X72.
So you see, that there is no need for an25 pin connector on the boards 
side :)

If someone wants to download the X72 designer guide here it is:




> Ed Palmer 
> <https://www.mail-archive.com/search?l=time-nuts@febo.com&q=from:%22Ed+Palmer%22> 
> Thu, 17 Aug 2017 22:11:47 -0700 
> <https://www.mail-archive.com/search?l=time-nuts@febo.com&q=date:20170817> 
> I did some more work on the HP printer cable that uses this connector. 
> Here's what I found:
> 1.  Pin 25 on the X72 connector is unconnected.
> 2. The connector is IDC. It's possible to open it up and add the extra 
> lead, but like all IDC connectors, it's rather fragile. 3. Of the 25 
> leads in the cable, 10 aren't connected through. However, the 
> disconnect is at the DB-25 end. All 25 leads are wired into the X72 
> end. 4. HP used both JST and Molex connectors. From the pictures I've 
> found, I can't tell if the Molex connectors can be opened.
> 5.  The connector appears to be model DMX as shown here:
> https://web.archive.org/web/20050313045224/http://www.jst-mfg.com:80/pdfE/eDMX.pdf
> It looks like you have to order all the pieces seperately (?).
> JST Connector: http://www.ebay.com/itm/182682094117 . Note the angled 
> corners near the cable. Molex Connector: www.ebay.com/itm/182474574277 
> . Note the corners are closer to square than on the JST connector. The 
> ideal result would be to find a source of new,unused connectors, but 
> these printer cables appear to be an alternative.
> Ed


Christoph Kopetzky

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