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Todd Willoughby

UC320 with Comcast Business Voice?

Quick question,

we have a client that is moving offices and finally wants to make the move to IP phone system. They are purchasing comcast business voice service. Will this service interface with the UC320 or do we need to move them into a UC540? This comcast service will also be forwarding via virtual number to their old exisitng ported numbers they are bringing with them from the old location, any issues with this as well? From what I understand Comcast will be providing some sort of EMTA modem that we can dirctly run phones lines into the FXO ports on the UC320? Any help would be great


Matt Waechter

How many phone lines? If more than 4 you will need a SPA8800 to support 4 additional lines.

I believe its only going to be 3. Two voice lines and one dedicated fax line.

Out of the modem they should appear as "POTS lines"; you can connect those directly to the UC320 via sure to run the FXO impedence testing to get the best voice quality.

Todd Willoughby

Thanks for the help the install went great today. Couple of follow up questions. How do I activate caller ID when the phone ring it just shows what fxo line the call is coming in on. Also where can I go to run the impedence test?

Hi Todd,

Please run impedance matching tool at Line (FXO) Ports page in Configure Utility. It should resolve caller ID issue. If not, please install Bellcore_CallerID.pmf at This PMF sets the caller ID standard to Bellcore.

Best regards,

Wendy Yang

I tried both of these soltuions above. I ran the impedance testing tool and that did not work I also applied the bellcore pmf file and that also did not work. When the line rings it just says FXO1 or FXO2 etc from what ever line the call is recieved from.

Also another question the folk that are using these phones want ot be able to tell if someone is on a active call if there a way to have a light come on next to the extension if it in use use by someone letting the person know that the person is either on the phone or on the line? The system is set to PBX mode currently

Hi Todd,

Please connect an analog phone directly to the phone line (bypass UC320W) to check if the service provider delievers the caller ID. If yes, please reduce the FXO port receive gain at the Line (FXO) Ports page in Configure Utility. If it still doesn't fix the issue, please contact Small Business Support center. One of our engineers will be able to help you to troubleshoot it.

If the extension is on an active call, the extension button is always lit on.

Best regards,


The caller ID funtion was not turned on by the phone company. I had called them and had this enabled it is now working properly.

Although the issue with the light on the extension still exisits. For example if a recpetionist awnsers a call and wants to transfer the call to someone in the back office who also has a IP phone (504G) there is no way to tell if that person is currently on a call already.

Hi Todd,

You can configure some line monitor buttons at the receptionist's phone. If the monitored phone line is on an active call, the monitor button is lit on. The following is the description of Line Monitor Button:

Line Monitor: Monitors the status (ringing, on a call, or on hold) of a single extension. Also known as Busy Lamp Field (BLF). (Not available for FXS phones and system extensions such as Auto Attendant.) It also functions as a Auto-dial (Speed Dial) button to immediately call a user or to immediately transfer a call to a user, without consultation. In addition, it can be used as an Individual Pickup button to pick up a call that is ringing on the specified extension. If multiple calls are ringing, the first received call is picked up. A device can have only one Line Monitor or Phone Monitor to monitor a user. Tip: This feature is useful for an administrative assistant who monitors an extension of an executive, and for co-workers who back up one another during breaks. Note:  This button does not reflect the user's activity on other extensions such as Shared Lines and Shared Extensions.

Hope it helps!

Best regards,


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