just thought i would share this with all, but after upgrading a site from 3.2 to 4.x we have found that if a 4424LD is plugged in to any module v1 or v2 it will knock down the WHOLE system forcing constant reboots. thought something major went wrong with the upgrade, but 3 hours later after disconnecting all the sets and pluggin them back in one at a time we found the bad phone. I know the phone was never offically supported, but it always worked on other releases. it would have been nice if they would mention this in the 4.x upgrade instructions. im sure there are hundereds of these phones in use out there. just thought i could save you some troublehooting headaches for anyone else that wuold be doing an upgrade that has one of these phones.