asterisk.ru

Починил.
Всё, что я сделал - это попросил админа на месте обжать другой кабель вместо того, который был между моей платой Е1 и железкой провайдера, при этом сказал ему сделать кабель максимально коротким, без скруток и категории 5, не ниже.
Факсы стали ходить.

Любопытно было бы увидеть как замена кабеля повлияла на
dahdi_test -v -c 100

[root@voip-brnl asterisk]# dahdi_test -v -c 100
Opened pseudo dahdi interface, measuring accuracy...

8192 samples in 8192.104 system clock sample intervals (100.001%)
8192 samples in 8191.785 system clock sample intervals (99.997%)
8192 samples in 8192.080 system clock sample intervals (100.001%)
8192 samples in 8192.064 system clock sample intervals (100.001%)
8192 samples in 8192.057 system clock sample intervals (100.001%)
8192 samples in 8191.993 system clock sample intervals (100.000%)
8192 samples in 8192.031 system clock sample intervals (100.000%)
8192 samples in 8192.097 system clock sample intervals (100.001%)
8192 samples in 8192.063 system clock sample intervals (100.001%)
8192 samples in 8192.063 system clock sample intervals (100.001%)
8192 samples in 8192.063 system clock sample intervals (100.001%)
8192 samples in 8191.760 system clock sample intervals (99.997%)
8192 samples in 8192.360 system clock sample intervals (100.004%)
8192 samples in 8192.096 system clock sample intervals (100.001%)
8192 samples in 8191.976 system clock sample intervals (100.000%)
8192 samples in 8192.040 system clock sample intervals (100.000%)
8192 samples in 8192.056 system clock sample intervals (100.001%)
8192 samples in 8192.048 system clock sample intervals (100.001%)
8192 samples in 8192.088 system clock sample intervals (100.001%)
8192 samples in 8192.016 system clock sample intervals (100.000%)
8192 samples in 8192.063 system clock sample intervals (100.001%)
8192 samples in 8192.063 system clock sample intervals (100.001%)
8192 samples in 8192.136 system clock sample intervals (100.002%)
8192 samples in 8192.000 system clock sample intervals (100.000%)
8192 samples in 8192.000 system clock sample intervals (100.000%)
8192 samples in 8192.096 system clock sample intervals (100.001%)
8192 samples in 8192.024 system clock sample intervals (100.000%)
8192 samples in 8192.040 system clock sample intervals (100.000%)
8192 samples in 8191.944 system clock sample intervals (99.999%)
8192 samples in 8192.176 system clock sample intervals (100.002%)
8192 samples in 8192.063 system clock sample intervals (100.001%)
8192 samples in 8192.048 system clock sample intervals (100.001%)
8192 samples in 8192.024 system clock sample intervals (100.000%)
8192 samples in 8192.024 system clock sample intervals (100.000%)
8192 samples in 8191.976 system clock sample intervals (100.000%)
8192 samples in 8192.041 system clock sample intervals (100.001%)

Однако кардинально повлияла замена кабеля