Three computers, a keyboard with USB triplexer

Many of us will have the problem of multiple computers on the same desk, and to avoid clutter we will use a KVM switch to share peripherals. [The Turbanned Engineer] has an interesting solution to this problem in the form of a USB triplexer. It is a device that routes USB data lines depending on the live connection.

The circuit is quite simple: a CMOS analog multiplexer does the routing and a set of opto-couplers do the selection based on the power inputs. One set of USB A plugs connects to the computer and one USB B plug connects to the device.

We're not sure if an analog multiplexer chip would be suitable for the faster USB data rates, but since keyboards and mice talk at the slowest data rates, we think it'll be fine. Anyway, making such a basic USB switch with such mundane components has something hack about it. We're not sure what he's doing with the screen, but at least his keyboard and mouse issues are resolved.

Other similar switches we've featured are a bit more basic.