The standard Gandalf units supports:
Gandalf proprietary Bandwidth-on-Demand
Optional POTS interface
Full 10BaseT or (optional) 10Base2 Ethernet connectivity
With the EdgeRouter option, you get:
Multi-Link PPP
PAP / CHAP authentication
ML-PPP Bandwidth-on-Demand
Here is a FAQ on how to setup a Gandalf 5242 Edge Router.