How To output the PXI-6608 OCXO to PXI_CLK10_IN

Hi!

I am trying to make high accuracy measurements with the PXI-6608.

I am using a 3rd party PXI backplane which has no StarTrigger slot that would override the PXI_CLK10 automatically with the PXI-6608 OCXO output PXI_CLK10_IN.

It appears that the PXI-6608's OCXO has no direct link to the time source of the counters but that instead the time source can "only" be PLL-synced to PXI_CLK10 signal of the backplane. Is this correct?

I tried to measure the high accuracy OCXO output on PXI_CLK10_IN but got nothing. What needs to have the PXI-6608 output its OCXO clock to PXI_CLK10_IN?

ThanXs for your help, Hezapeter