The Extron SW2 USB, SW4 USB, and SW4 USB Plus are two- and four-input USB switchers that allow switching between multiple host devices and multiple USB peripherals. They provide integrator-friendly solutions for implementing USB 2.0 compatible switching in professional AV environments. A number of specialized features help further streamline integration, such as: port status indication, RS-232 pass-through, front panel security lockout, and multiple control points. The SW4 USB Plus model features Host and Peripheral Emulation Mode, which provides “keep alive” functionality by continuously mimicking host and keyboard/mouse communications within the switcher. This emulation eliminates the need for enumeration, and reduces the chance of failed device communications throughout the switching process. All of the SW USB Series switchers act as active USB hubs, supplying 5V, 500mA to attached devices, per USB specification. In addition, the switchers are USB 2.0 compatible, and are backwards compatible with all previous USB data rate specifications, including low speed 1.5 Mbps, full speed 12 Mbps, and hi-speed 480 Mbps. RS-232 pass-through reduces RS-232 control port requirements by processing SIS commands within the SW USB while also passing them through to other controllable Extron audio and video switchers. The SW USB Series incorporates rack mountable, 1U, half-rack width enclosures for simplified integration. All models include an external, universal power supply for worldwide power compatibility.