Question : Cisco VOIP Dialtone Issue

I am having a very strange problem with some of our Cisco phones.  We are running Cisco Callmanager 5.1(1) and mostly 7941 phones (a few 7911 and 7970).  I have had 7 7941 phones over the past week or so that started having problems getting a dialtone when lifting the handset.  They get a dialtone all the time when hitting the speaker button.  I've been working with Cisco (did a bunch of traces) and they think that (atleast with the one we test on) that the phone itself is bad.  I had a new 7941 phone that we were able to register and it is working properly in place of the one that was bad.  However, I have had sever 7941 phones that had been used before but had been taken out of service because they were not needed that I can not get to work properly.  Same problem - no dialtone from handset.  I am finding it very odd that I would have this many phones in this short of time that are having this problem. We have checked firmware version, reregistered, went back to factory defaults and still no luck with them.  Any ideas please??????  I am getting stumped.

Answer : Cisco VOIP Dialtone Issue

I was able to resolve the problem on my own. Found that the hookflash needs cleaning.