The MCX128 is an expansion module for the TRS-80 MC-10 or Matra Alice 4K. It adds 128K static RAM and a socket to accomodate a 27128, 27256 or 27512 EPROM.
The board is supported by an extended version of the MicroColor Basic interpreter (MCX Basic) which needs to be programmed into the EPROM. MCX Basic adds many of the language features found in Extended Color Basic for the Tandy Color Computer (CoCo). It also supports using a PC/Mac or other host device as a file server.
Links:
Documentation:
MCX Docs (pdf)
Emcee File Server for MacOS:
Emcee Server App
PyDriveWire Server (python, multi-platform):
GitHub Repository
Latest Project Files (December 2019):
MCX128 Essentials
Purple PCBs:
OSH Park