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

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. And see here for current known issues.

New Member

Expanding my CME

I found out that i need more than 48 phones in my network. Do i need to buy a new IP PBX 2821 or can i upgrade the device to support more phones?

Hall of Fame Super Red

Re: Expanding my CME

Hi Walid,

The number of supported phones is based on the Router platform and Memory (like you have correctly noted). You will need to purchase a new box :(

For example: Here is the number for a 2811,2821 and 2851 with CME;

Cisco 2811

Maximum Total IP Phones 36

Cisco 2821

Maximum Total IP Phones 48

Cisco 2851

Maximum Total IP Phones 96

From this good CME doc;

Hope this helps!


Hall of Fame Super Gold

Re: Expanding my CME

Rob gave the official numbers.

Here the actual ones, that are larger because Cisco in their grace, gave customers a little of slack:


Phones DNs Phones DNs

1751 (CME 3.2) 30 150 100 N/A

2801 30 150 24 144

2811 42 144 36 144

2821 ?? ?? ??

2851 96 288 96 288

3825 168 500

3845 240 700

Hall of Fame Super Gold

Re: Expanding my CME

You cannot increase the limit for ephones on a router and no upgrades are available.

However, if you can live with the differences and limitations, you could add an equivalent number of ephones, because the software does not enforce the sum of SCCP and SIP phones against the maximum supported.

That would be a unsupported configuration, of course.

Hope this helps, please rate post if it does!