Cable Modem Question

I don't know if this question can be answered here or not.

I have a Motorola cable modem that has an IP address that I can access the modem software.

The modem was just replaced with a Arris cable/phome modem to add a cable phone and higher internet speed.
Does anyone know how to access the IP address of this modem?
No special reason to do this other than curiosity to see what it looks like.