The Westell Gateway is a DSL modem and yes, you can connect it to the WAN port of a Router.
But that's not going to solve any speed issues as your bandwidth is dependent on several factors.
- 1) Distance from phone company or relay station
- 2) Quality of the phone lines
- 3) Which DSL package you paid for
DSL packages are 768 Kbps - 1.5 Mbps or 3.0 Mbps
- 4) Inside interference in your house (appliances, florescent lights, etc)
- 5) Malware infections using up your bandwidth