Hardware Specs
For the Memotech, you don't need an RF to composite convertor - it has composite out anyway.
The RS 128 was the same size as the MTX500/512 - it just had the RS232 ports and extra memory as standard, rather than being options.
The serial ports (when fitted) were RS232.
The lighting controller would have been interesing - the User I/O Port was a nice feature that I don't think was used by many people at all
regards
Dave