I did, using linux and oh323 channel driver.
It works really bad using G711, I bought some G729 licences from digium and it started to work well.
Using G711 I was getting a choppy voice and I found no way to make it work properly.
Here's the steps I did :
-Install asterisk
-Install OpenH323 along with pwlib, lzo and asterisk-openh323 (read the h323 documentation I think it depend on a specific versions of pwlib)
-edit /etc/asterisk/oh323.conf and add the ip address of your avaya in the gatekeeper config
You need an IP Endpoint licence in avaya.
Problems I still need to find solutions :
- I've got no ringback sound when a call come from the avaya and ring to an asterisk extension
NOTE: I did bridge an asterisk server using a T1 card to the ip office and it fixed almost all my OH323 problems.
I would say oh323 is the cheap solution (that may be buggy too), and T1 is very reliable but more expansive. If you're doing this for your personnal growth, then its okay, but for a production box I would go for T1