Framework for controlling passthrough mode is disclosed herein. Exemplary passthrough apparatus may include a relay, a first connection interface connectable to a first universal serial bus (USB) host device, a second connection interface connectable to a USB client device, and a third connection interface connectable to a second USB host device. The passthrough apparatus may further include a housing enclosing the relay and the first, second and third connection interfaces, wherein the relay communicatively couples the second connection interface and the third connection interface while communicatively decoupling the second connection interface and the first connection interface in response to disconnection of power to the relay during a passthrough mode.