I get the message (see attached image) saying that QoS isn't enables with this IOS. i check my IOS, it says 12.4(4)T.
is QoS possible with my 851W?
Sorry, the 851 does not support QoS.
However I have one at home, off a decent adsl, and I have no issues with voice in g711 even with concurrent data activity. of course this is not merit of the router but of said decent service.
Hope this helps, please rate post if it does!