Savant Lighting Controller Custom RS232 Cable


On our latest job, we are using a Savant SmartMediaPro 6 (SSP-06004) as the main AV matrix switcher and controller for the house.  We are using a SmartLighting 18 (SSL-P018) as the Savant lighting controller.  They are both mounted in an equipment rack.  The way we connected the two is using the RS-232 Integration ports on the SSP to connect to the SSL.

In Blueprint it is easy to setup this connection between the controllers.  It took a little time to deduce how to create the custom cable.

FIRST TRY:  We made up a standard ethernet patch cable (basically terminated RJ-45 connectors on the end of our CAT-5e cable.)  It didn’t work.

SECOND TRY:  Then we took two of the colorful RS-232 connectors (the ones that come with the Savant 0007 controller) and coupled them to two common CAT-5e patch cables.  So we had one patch cable from the SSP’s RS-232 RJ-45 port connected to the Red RS-232 connector, then we had a DB-9 Male to Male Gender changer, then the Yellow RS-232 connector and then another patch cable to the RS-232 integration port on the SSL.  This worked.

(But it was ugly and we didn’t want to leave the colorful RS-232 connectors on this job!) In the “Notes” dialogue box for the SSL’s profile it states this —

“You can NOT use a straight ethernet wire.  You must swap Pins 5 & 6 (on only 1 of the 2 connectors).”

THIRD TRY:  We made up another CAT-5e cable with RJ-45 connectors on each end and on one end we reversed connections 5 and 6. (Kind of like an ethernet cross-over cable.)  This didn’t work either.

We plugged our Frankenstein cable back in and the two controllers began to talk. Hmmm… So we took out our meter and and began to tone out the cable that worked. What was the difference between the Frankenstein cable and the one we had made up with the reversed connections 5 and 6?  So we toned connection 1 to connection 1 – nothing, no connection. 2 to 2, same thing, no connection. 3 to 3 and so on.

What we found was what we expected: 4 connected to 4, 5 connected to 6, 6 connected to 5. So we toned out our custom made cable and guess what?  It was the same!  4 connected to 4, 5 connected to 6 and 6 connected to 5.  But for some reason, the one cable worked and the other didn’t.  By the way, when we swapped in the Frankenstein cable, we didn’t change anything in the controllers, we didn’t update any programs, just connecting the cable made the difference.

So here is what we did:  FOURTH TRY:  we remade our custom cable end one more time.  This time we didn’t connect connection 1, 2 or 3.  We only connected connections 4, 5 and 6.  And didn’t connect connections 7 and 8.  We plugged in our cable and it worked.  So somehow the controllers sense the connections on 1, 2, 3, 7 and 8 and reconfigure themselves (a pull down resister?) so that the RS-232 doesn’t work.  Here is drawing of how we connected the RJ-45 connectors.  Remember to reverse connections 5 and 6 on one end only.


This cable works.