No Dial Tone? *But Display Works*

[norstarboston]

I am running a system with about 60 sets but recently there always seems to be one that will not get a dial tone but will display like it is normal (time/date etc, it even rings if you dial it). But once you try to make a call all you get is Silence. If you pull the plug and reset it a couple of times it goes back to normal but then it just occurs on another set(m7208). It appears there are 3 sets passing this "disease" around. Anyone know a solutions or probably cause?

 

[sprucegrover]

Have a look at this thread thread799-468890 and see if the symptoms are similar, which they seem to be, and if the software is the same. I have also had the problem on MICS R4.0 which went away after it was changed to R4.1 WI6.15