Motorola SURFboard SB4100 38 Mbps Cable Modem. The SB4100 offers both Ethernet and USB interface connectivity to help ensure compatibility with almost any PC or Macintosh network-ready computer system. What's more, a front panel stand-by switch has been added for additional end-user security. It disconnects the USB and Ethernet connection to the CPE without disconnecting the cable modem from the RF network, providing security, flexibility and performance.