There's only one actual oplink, it's real name is actually oplink-mini. It has not only the radio module but a STM32F103CBT6 processor that handles the protocol. Real oplinks have two 4 pin serial port connectors, a micro usb, and a connector for the antenna. Some have a 4 pin debugging connector but about half the clones I've seen don't bother to put it on. Some have a "bind" push button, some don't. It doesn't matter because it's not used. The ones used on the ground end of the link are the same as the ones used on the quad, there really isn't an "oplink ground" as the Chinese call it. That one is just another oplink-mini clone.
The Chinese "oplink-air" isn't really an oplink, it's just a RFM22b radio module and a voltage regulator. All of it's processing is done by the mini-revo it's attached to. And that's the only thing it can be attached to. It has a 7 pin connector and a connector for the antenna.
The oplink-mini just plugs into a serial port that's set as telemetry. It would work on the Falcon F4, a revo nano, or even a cc3d.