Dear Ivan,
On Mon, Oct 12, 2020 at 12:26:22AM +0300, Ivan Babanov wrote:
I heard that it happens on some hardware with Digium cards, I'll try tomorrow to change PCI slot to avoid sharing one IRQ with USB devices, maybe disable USB at all. If it doesn't help, I'll try a new server with different HW.
I'm sorry but I think you are looking at the wrong level. I doubt that the hardware is the problem.
If you are worried about the hardware/OS/drivers, just use a loopback E1 cable between two ports and run e1-prbs-test (from osmo-e1d/contrib) on both sides to see if you can communicate between two ports. If that works, you can exclude any problems related to hardware or drivers.
If you have connceted span 1 + 2 via loopback, start
in one shell: e1-prbs-test /dev/dahdi/chan/001
in another shell: e1-prbs-test /dev/dahdi/chan/002
and check the stdout to see if they find sync in both direction.
This program sends pseudo-random bit sequences over every timeslot and checks that the correct PRBS sequence arrives on the other side, bidirectionally.
Regards, Harald