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To insure your clocking is setup correct please go to https://wiki.freepbx.org/pages/viewpage.action?pageId=79138050 How Do I Configure Clocking? and go through the per port configuration and the per card configuration sections. If you needed to make changes to your clocking then please do so and restart our driver and check for overruns. If the overruns occur even after clocking issues have been resolved then proceed to the next step.
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In Master mode you don't know if the other side is providing a clock as well on the line. So example #3 at https://wiki.freepbx.org/pages/viewpage.action?pageId=79138050 How Do I Configure Clocking? can be occurring, so place the port into NORMAL clocking and see if the link connects. If it does then the other side is providing a clock, if not then MASTER mode is the correct mode to be in.In Normal mode if the link is in the "connected" state then this means the other side is providing a clock and this is the correct setup.
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The DMA engine uses a single clock per card to pull data from the ports, so this is why having as single clock is very important as shown at https://wiki.freepbx.org/pages/viewpage.action?pageId=79138050 How Do I Configure Clocking? in the per card section. The different clocks will cause the DMA engine to be out of sync for some ports (ports with the second clock) and therefore cause overruns.
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