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UC320 PBX sip trunk problem

HI, I installed the UC320 for a customer and they have 19 users,  we are using sip trunk for voice traffic

it now encountered an annoying problem, The  isp is doing the maintenance in recent period and their sip trunk is coming down and up occasionally  at night.  Whenever the sip trunk broke and come up again, the UC320 seems loss the sync with the wan, and it can work for 1 or 2 days and then the phone can not dial externally and also the incoming call have the problem, Yet the internal call is ok, whenever, this happened, we need to restart the uc320 to resume the service.  I configured the auto maintainance happen at Sunday morning 3am , yet, there are times that the sip trunk broke happen on Monday night, then we usually get the complaint from the custom around Wed. or Thurs.  and then we had to restart the system to resume the service.  It is really troublesome. Do you have any idea how to deal with the problem. Is it a bug of cisco uc320? Is there any software update or any  patch for this problem?

We are running 2.3.2(6) now.


UC320 PBX sip trunk problem

Hi Rex,

The SIP trunk status is changed to unregistered after ISP did the maintenance. UC320W needs to be restart to send REGISTER message to ISP to register the ISP trunk to bring it up. It works as it's designed.

Best regards,


Community Member

UC320 PBX sip trunk problem


Thank you for your reply, but the thing seems a bit more complex, our network configured as unregistered by the requirement of isp, and it works nicely. when the sip broke down and come up again, the pbx can work normally for 1 or two days and then it seems drifted away. and the problem at  beginning is minor with only a few phones malfunction, and can be retored by restart the phone, but as the time goes by , the problems seemd deteriorated until all phones not working and we have to restart the pbx. 

     I check the external trunks, the status of sip is unregistered. it is required by isp to be configured so. it works nicely as long as the sip trunk is on.


Community Member

Re: UC320 PBX sip trunk problem

Check the switch firmware upgrade it that helped me

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