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.