We are trying to set up a wireless service to transport our office VOIP. The AP's actually in use are th RB4XX with RB52 cards already in use for the data service. We are totally unable to register both the Policom 8440 as well as the CISCO SPA525G. We suspect some problem related to the implementation of the WMM protocol that disallow the terminals to register to the APs.
Considering the fast growing of the VOIP this issue is going to became of impact on the existing wireless network and if there is not any official position taken from the Mikrotik guys, it seems the only possible solution to switch over to the Cisco Aps.
Any suggestion?

I've bumped into the very same issue using RB951g with ROS 6.7 and ROS 5.25 (two boxes).

A friend of mine managed to get the spectralink 8440 connected to his RB493g using a b/g wlan card about a year ago. He remember he messed about a lot to make it work, but finally he got it. Surely he didn't make notes on what he did, and he no longer has this config. He surely did not do anything in firewall mangle as he wasn't aware of the mangle menu in winbox.

So, all I know is that this is possible somehow.

After some discussion with spectralink we figured that the accesspoint needs to support WMM-PS or WMM-AC in order for the handset to connect. I found a statement from mikrotik dated 2011 that PS is not supported. Is that still true?
I haven't found anything regarding mikrotik and WMM-AC. Could it be enabled somehow?