Difference Between Different UC520 Form Factors

Unanswered Question
Apr 23rd, 2009

Hello All,

I see different photos of the UC520 on web all the time. The different photos show the UC520 in different form factors. Some of the form factors have additional ports than the others.

My questions are what's the difference between all the form factors?

What are those additional orange ports?

Why does the bottom unit in the second image not have the built-in FXO ports?




I have this problem too.
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Steven Smith Thu, 04/23/2009 - 10:14

The different form factors support different users.  The small ones support 8 and 16 users.  The large ones support 24 and up users.

The differences in ports are for FXO, BRI, and T1's.  There are several SKUs of UC500.

Here are some of the SKU's







The 3rd part of the sku gives a description about what the box comes with.  Some of the boxes in the pictures are switches as well.

Note, only the 8 and 16 user sku's have wireless.

Skyler Spence Thu, 04/23/2009 - 10:15


The different form factors correspond with both different numbers of users supported (8/16, 32/64) and different PSTN connectivity (FXO, BRI, T1).  The orange ports are BRI ports in that photo.  Also note that some of these pictures feature the CE520 expansion switch along with the UC520 model.

jaydien1358 Thu, 04/23/2009 - 10:46

ok. yes I realize that there were switched also shown in those photos. But what about the large form factor? That one is for 32 and up users? And what is that single port above the FXS ports for? It looks like it is yellow.

Also, how do you fit 12 FXO ports in the UC520. I know that it has 4 built in and you can add an additional 4 through the VIC slot, but what about the last 4 ports?

Lastly, where can I get a list of all possible skus?



Steven Smith Thu, 04/23/2009 - 10:51

That looks like a T1 port to me.  The larger chassis are for 24 users and up.

You can get 12 FXO because you can get the larger chassis to have 8 built in FXO and 4 FXO in the VIC slot.

jaydien1358 Thu, 04/23/2009 - 11:02

ok. So this chart that I found on this site shows the following PSTN capacity:

PSTN Trunks Capacity of UC520 Models

UC520 modelPSTN InterfacesNo. PSTN-VoIP channelsNo. PSTN-VoIP channels
With FXO or BRIWith E1
UC520-8UFXO(4), BRI(2)4NA
UC520-16UFXO(4), BRI(2)4NA
UC520-24UFXO(8), BRI(4)8NA
UC520-32UFXO(8), BRI(4)8NA
UC520-48U No T1/E1FXO(12), BRI(6)12NA
UC520-48U With T1/E1FXO(4), BRI(2) and T1/E1430

For the first one listed, I assume that the BRI interface has tho be an expansion card in the VIC slot? If that is the case, does that mean that there is a 2 and 4 port BRI cards. Also, how to you get 6 BRI ports? Would the UC have to be shipped with builting BRI ports at that point?

Thanks for answering my remedial questions. :)


Steven Smith Thu, 04/23/2009 - 11:15

On the 8U and 16U SKUs, you can have 2 BRI ports instead of FXO ports.  BRI is much more popular and Europe instead of FXO.

On the 24U and up SKUs, if you go with BRI, there are 4 built in ports.  You could expand to 6 with a 2 BRI card.

You could use this link.  Scroll down to ordering info (pretty far down).  It has descriptions of lots of SKUs.


jaydien1358 Thu, 04/23/2009 - 12:19

Thanks for the help. I think I am clear now.

I posted the different models and form factors with their specific options on our website. If you want to take a look to see if I have done an accurate job, here is the link:




jaydien1358 Thu, 04/23/2009 - 12:39

Yes I didn't want the page to get overwhelming. But I am going to include a link to that page though.



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