Avaya 3631 with Remote ACM without VPN tunnel??

[sibuor]

Hello guru,

I am very new to all this, and so count on those who have walked these paths.

I have an ACM (5.2.1) co-located somewhere, behind a Cisco 2811 router.

Then I have my boss who likes mobility and so I have bought an Avaya 3631 for him. He uses ADSL connection at home and so I have also bought Cisco 877w for the ADSL connection and Wi-Fi.

Is there a way I can get the 3631 to connect to the ACM without establishing a VPN tunnel between the two Cisco devices?
I am thinking about the ability (if any) to just open certain ports on the Cisco 2811 and redirect those to/from the ACM IP.

Anyone been there, done that??

Or must I establish the VPN tunnel?

Thank you.