Cisco Support Community
Showing results for 
Search instead for 
Did you mean: 
Community Member

UC320W is disconnecting Calls.

We have a UC320W with firmware 2.3.2 firmware.

we have 2 analog trunks coming in to ports 1& 2 of the FXO ports and are connecting to shared FXO ports available to all phones.

I've tried testing the FXO ports with the internal tests and they appear perfectly functional.

We are constantly getting incoming calls disconnected. Incoming calls will ring and when we pick up there is no one there, and the customers call in again complaining of being disconnected.

I've tried changing internal building wiring and the ports that the analog trunks connect to.

We have discovered that the incoming calls are coming in at 53 volts, and I believe that the UC320 will disconnect if the voltage is higher than 48.

Can any confirm that this is true, or if they know any other reasons why calls would constantly be disconnected.


System contains:

1 - UC320W

8 - SPA504G

1 - ESW520 POE 8 port switch

Included a Copy of the site programming


UC320W is disconnecting Calls.

Hi Christopher,

Could you please send me an email at I will reply you with a PMF to resolve this issue because I think you may hit to a known bug.

Best regards,

Wendy Yang

CreatePlease to create content