Even though it’s no longer used for hi-fi any more, you will still see ports like this on nearly every piece of MIDI gear. These cables became obsolete in the 1980s, and when MIDI was invented in 1983 many Japanese manufacturers had lots of back stock of them that they needed to get rid of, so they decided to make that the first MIDI cable standard.
Those cables with the round 5 pin connectors (officially called DIN 41524 connectors) were originally used as hi-fi cables way back in the 1970s. There are four ways that MIDI can be transmitted using an iConnectivity interface: MIDI is like an electronic version of that. The conductor doesn’t make any sound by their self, but they send signals to all of the other members of the orchestra that tell them what to play, when to play, and what expression to use while playing.
In this sense it works like the conductor of an orchestra. It’s important to realise that MIDI doesn’t contain any actual sound itself, it’s simply instructions for how other instruments should create sound. It consists of a set of digital signals that are used for controlling and playing electronic musical instruments. MIDI stands for Musical Instrument Digital Interface.
