Example implementations relate to transmitting signals via USB ports. For example, a system according to the present disclosure, may include a host module including a plurality of USB ports, a first expansion module, and a second expansion module. The first expansion module may include a first USB port and a second USB port. The first expansion module may receive a signal from the host module at a first USB port, and direct the signal to a second USB port. The first expansion module may transmit the signal to a second expansion module via a second USB port.