I recently had a nightmare building up some servers with these OpenVox cards.

Although I have used them successfully in the past, the chan_extra driver building process has always been highly temperamental (although to be fair, they have always worked fine once any necessary tweaking was done).

However, chan_extra will not build against the latest DAHDI; and older DAHDI
versions will not build against the stock kernels in Debian Jessie or Ubuntu Precise. I was just fortunate that the motherboards worked with Debian Wheezy.

OpenVox have advised that the G400P/E is an end-of-life product and as such, updating its drivers is not a priority for them. And I am not sufficiently qualified in low-level programming to fix this myself. They recommend their GSM
gateways (which I have not yet evaluated) instead.

If anyone is thinking of using these cards for a project in the near future, make sure the motherboard that you are about to use will boot an old kernel
(Wheezy has 3.2.0-4) in order to be able to use sufficiently old versions of Asterisk and DAHDI (1.8.22 and 2.7.0 + 2.7.0 definitely work with chan_extra
2.0.8; I grabbed the .tar.gz files straight out of /usr/src on a similar machine I built earlier). And it probably wouldn’t be the best idea to have the machine facing the public Internet while it’s running such obsolete software. Fortunately, these ones will be safely on the inside of a firewall.

See also here: http://www.openvox.cn/forum/gsm-wcdma-series/2910-g400e-
chan_extra-2-0-8-needs-old-software.html