Monitoring E1 link channel usage

Monitoring E1 link channel usage

Hello there!
This is Valdecir, from São Paulo, Brazil!

Anyone could please help me to find how to monitor a E1 link (the same as T1 in US) channel usage?

The voice gateway is a Cisco Router 2911.

I can see the information about the channel usage on E1 running this command:
> sho voice call summary | inc 0/0/0

I want to show a graph like this one (got this on a Cacti forum).

Thanks in advance