USB Powered - no batteries or power adapter required. USB plug is built into modem. USB version 1.1, 2.0, and 3.0 compliant Supports the latest dial-up modem standards and faster Web browsing with V.92, V.90 and V.44 Fast Connect Times with V.92 QuickConnect Fax Support - a Windows or Mac OS X (v10.6 or later) computer is required Compact Size - Great for the road or the office. The 3095 USB Mini External combines a highly efficient design, easy installation and high performance in a surprisingly low-cost product. With its small size, light weight and integrated USB cable, the 3095 is perfect for travel or home office use. The modem plugs directly into a USB port and works with any operating system supporting a USB interface, including Windows, Macintosh, or Linux. Configuration is automatic and reliable without the potential conflicts of an internal modem. And the USB port provides power to the modem, so you don't need a power cube. That means no bulky power cube when you travel and no power cube clutter at your desk.
I got this for someone who acquired a MacBook Pro but is still on dial-up. (Recent-model MacBooks don't have internal modems.) It was literally plug and play. A big relief! Didn't even need to load any software. It's been a few weeks and there have been no problems at all getting online.
One side note: It needs to be plugged into the actual USB port vs. a USB hub as the hub isn't going to have enough power for it.