Abstract: Aspects relate to techniques for controlling signal voltage levels across a wired data link for data communication between apparatuses. A first device can advertise multiple supported signal voltage levels to a peer device connected by the wired data link. The devices can implement the same signal voltage level(s) or different signal voltage levels. The peer devices can compare and select a compatible signal voltage level for data communication. The first device can provide a signal voltage indication signal that is configurable to a plurality of voltage levels corresponding to a plurality of signal voltages. At least one of the plurality of voltage levels can indicate that the first device can operate the data link at a plurality of signal voltages. In some examples, the wired data link can be a peripheral component interconnect express (PCIe) link.