I found a seller of 1996-era CD-ROM
“Mitsumi” JST audio cables on eBay. They use the exact same plug as the UARTs on the Mele A1000G Quad. The pins are 3.3v POWER (do not wire up), TX, RX and GND.
I started by butchering the CD-ROM audio cable:
The shield is the black cable (RX). The white is TX. The red is GND.
I also butchered the CP2102 cable:
I hooked the respective cables together, put a small blob of solder on each joint (just to improve electrical connectivity, it’s probably not necessary), then wrapped each joint then the whole bundle it in several layers of electrical tape:
I finished off by drilling a small (¼”) hole in the top of the case for the cable:
(And it works too!)