YG:
If you have a Technical Management position for an Airbus Operator, you should have access to the Airbus World site; thats the best way to go. There are also adresses directly to the technical deptarments in Toulouse for every system, this is also only for Airlines that operate Airbus; certainly not for curious people on a forum. If you have any questions, feel free to pm me.
mcdhu:
An EMERG DESC from 390 and 310 should be exacly the same, the ONLY difference should be about 2 minutes to get to the desired altitude, noting ugly. Worst case scenario is that the the mask will drop, nothing else.
G