digital extension out of service on MERIDIAN 11C

[Kahlaoui1980]

Hi all ,
Can some one help me , we have srious problem .
In fact ,wi have a meridian 11c with 350 Digital sets (M3901) , many extension some times go off service ( became inactive) .
Does s b have an idea or a solution ?

 

[loop13]

check at ld 22,prt,ovly if at drol has 30, if yes change it

 

[DFKSydney]

A wild guess....

If you have particular phones that are going out of servicebut check the polarity of the lines into the sets.

Also, maybe the firm ware versions?