The "porch" (formally the JEM-EF (Japanese Experiment Module - Exposed Facility)) had a matching connector on it that mated with the connector in the pictures above. This picture shows the shuttle arm holding the JEM-EF and the mating connector.
The coarse alignment guides on the two connectors interface with each other; the circles are electrical and data connectors.
The most interesting thing about this connection was the differing philosophies between JAXA and NASA regarding the process of connecting the JEM-EF to the JEM-PM (Pressurized Module).
In a cursory fashion, the process could be described as
- Robotic arm places JEM-EF in mating position
- Crewperson sends command to mate interface
- A short time elapses while mechanisms drive
- Crewperson receives indication that interface is mated
NASA wanted to know what troubleshooting telemetry was available if #2 was done and #4 never happened. JAXA's answer was: None. The mechanism was well designed, well built, and well tested, there is no reason it won't work.
The upshot was that the shuttle commander ended up being tasked with exposing the pertinent cabling under the JEM-PM panels, hooking a Fluke multimeter ammeter attachment around the pertinent cable, training a video camera on the multimeter screen and downlinking the image to the control centers. So the ground could watch the amps on the mechanism as it drove.
The mechanism worked perfectly.
Source: personal experience
Photo source: NASA