I also have the same problem. I use Nextiva's hosted service with 4 SPA504g phones. I chose Cisco phones because I thought they would be the most stable and I have had good experiences with cisco products in the past. It seems to be not the case in this instance.
I have called Nextiva 4-5 times about this, have upgraded the firmware 2 times, and am currently running 7.4.9c. Nextiva's customer service told me this was going to fix the problem but it didn't. The upgrade did make the freeze-up's occur less frequently but they do still occur. I did have the phones all coming out of a switch but removed it and have all phones plugged directly into the router. This also seemed to lengthen the time between freeze-ups but they still occur.
I guess I'm going to have to get on this list to try out the new firmware. I just hope it comes soon. It's just really annoying that I'm the one that was trusted to purchase the phone system and now everyone in the office is giving me grief about the phones freezing up. Everyone else wanted to go with an older system with the local phone company but I convinced them to go with this setup. We are a startup and this is not helping with our image. When people call and the phone doesn't work it makes us look like we don't have our act together. No good for a 1 year old insurance agency desperately in need of clients!
Best of luck to everyone. I hope this fix comes out soon.
I did some reconfiguration on our network in preparation for a VPN installation, and I changed the IP ranges that our internal network uses. Instead of the standard 192.168.x.x, I switched to IP's in the 10.x.x.x range. Since I did so, I haven't had a single phone on our network freeze for just over three weeks now - after experiencing almost daily freezes on some for quite some time. I didn't change anything else since the last attempt to fix, and I haven't updated any firmware yet, either.
I hope this helps someone else out there.
Have many customers also experiencing this and glad not only people.
we went to 7-4-9c and still same issue
have applied 7-5-1 today in vain hope it works. will fidn out in due course and update results. may be a while as upgraded them to 7-4-9c about 4or5 weeks ago and we all thought was resolved until today.
7.5.1a does not fix the issue.
We decided to stop purchasing the Cisco phones, going with Polycom. The 942 (Linksys) works great, the 504G remains problematic.
We are having a similar problem... transfering a call from an extension to another one. The last phone engaged on the conversation freeze and we need to power cicle the phone.
Cisco IP Phone SPA504G with latest formware 7.5.1a
Any idea? The Support said the problem is't related to the phone ???