Cisco Pbx Like The Cisco 2621XM Router, Can The Cisco 2620XM Router Do VOIP PBX As Well?

Like the Cisco 2621XM router, can the Cisco 2620XM router do VOIP PBX as well? - cisco pbx

I am new to the voice, and I am studying for CCNA and CCNP then used to, I want to explore CCNP and VoIP in general. I want to create a direct link with a friend's house and a phone at each end. So, maybe get two here to test.

I'm sure I can do research on the configuration of each router, but not difficult for me? You also need a software (or just as a mediator for e-mail / voice?).

I'm getting a 2620XM for a hundred dollars cheaper than the 2621XM ($ 200 instead of $ 300) and if I get two for each link and one for local use, would be perfect.

I am a student and I'm not exactly on the money. If you have an alternative proposal, and please do not hesitate.

Thank you!