OpenLink is a physical interface and a communication protocol that does data and power in the same cable. It is designed by DEV Joni to be used in various devices.

Most modern connectors (for example, USB and HDMI) are not feasible to build from ground up because they depend on factory-made parts. We believe that open-source devices have to be build-accessible to stand the test of time. We designed an open-source connector that anyone could put together in their garage - provided soldering tools, M3 screws and nuts and some metal strips. In addition, most modern connectors focus on making themselves as small as possible. This thrive trades off robustness. In scientific and industrial settings, having a reliable connector is better than the smallest one.

We decided to build the connector's data delivery around the already exciting I2C protocol because it offers relatively fast data transfer speeds, supports up to 127 devices, requires only two additional wires, and most importantly, is supported by virtually all micro-controllers and single-board computers. We added few formalities on top of this protocol to make it easy for all the OpenLink devices to communicate together.

For the power, we decided to use 12 V because most micro-controllers and single-board computers have integrated voltage regulators that can handle up to 12 V. It is possible to to use lower or higher voltages if all the devices connected in the bus can handle them. The default connector and cables can handle up to 10 A continuous current safely. Multiple power-sources and circuit-separators can be used to drive many high-power devices. When a single device needs more than 10 A, it seems reasonable to design heavy-duty versions of the connectors and cables that can pass perhaps up to 8 times more current safely.