The MAC Address can be found on a label on the bottom of the Router.  You can alternately find it by doing the following:

1. Open your web browser and type the IP address of the TW100-S4W1CA in the address bar. The default IP address is 192.168.0.1. At the LOGIN, input admin for the username and leave the password blank, click on LOGIN, and then click on Advanced Setup.  Click on WAN and then on Dynamic IP on the left hand side of the page.  On the right hand side of the screen, you will see six box's with the MAC Address.