A system, such as a server rack, includes rack mountable devices that communicate using one or more extremely high frequency (EHF) communication devices. A rack mountable device includes a rack mountable chassis including multiple sides, and a circuit board along a side of the rack mountable chassis, the circuit board having a surface. The EHF communication devices are positioned along the side of the rack mountable chassis and attached to the surface of the circuit board. Each of the EHF communication devices is configured to convert between an EHF electromagnetic signal and an electrical data signal. The EHF communication devices form EHF communication channels with other EHF communication devices in other rack mountable devices, or in the server rack to provide high bandwidth data transfer utilizing space on the sides of the rack mountable device.