Note that there are two different types of DIN-jack adaptors for MIDI, type A and type B. The Iridium manual does not say which one they use, so some research will be necessary.
TRS To MIDI Male Type A
Akai Pro, IK Multimedia, Korg, Line 6, littleBits, Make Noise
Pin 5-Tip (Current Sink)
Pin 4- Ring (Current Source)
Pin 2 – Sleeve (Shield)
TRS to MIDI Type B
Arturia, Music1010, Novation
Pin 5 – Ring (Current Sink)
Pin 4 – Tip (Current Source)
Pin 2 – Sleeve (Shield)
This info came from [Updated] How to Make Your Own 3.5mm mini stereo TRS-to-MIDI 5 pin DIN cables –
