I have come across several times, though, a cable that only has 2 twisted pair of cables with only 4 of the pins being used and the remaining pins of the RJ45 connector left open.

Apple’s $130 Thunderbolt 4 cable could be worth it, as seen in X-ray CT scans It helps if you see what's deep inside $10, $5, and even $4 USB-C cables.

The PUC I tested arrived with a basic instruction booklet, a couple of AA batteries (though it also has a Micro USB port for backup power), and a standard 5-pin MIDI cable.

But the good news is everything gets a whole lot easier with puc+, an upcoming palm-sized Bluetooth MIDI interface from Zivix that lets us connect MIDI controllers to iOS and Mac wirelessly.