Products

Memotech products, and what they included :-

Picture Description
MTX500, containing MTX motherboard (32KB RAM), external PSU. You could optionally add the MTX serial card inside. Ran BASIC.
MTX512, containing MTX motherboard (64KB RAM), external PSU. You could optionally add the MTX serial card inside. Ran BASIC.
RS128, containing MTX motherboard and MTX RAM card (giving 128KB RAM total), MTX serial card, external PSU. Ran BASIC.
MTX Series 2, which was like the MTX512, except that it had 256KB RAM directly plugged into it, a selection of yellow wires on the back of the motherboard, and an alternative address decode PAL. Usually only 64KB is visible in RELCPMH=0 mode to MTX BASIC. 208KB is visible in RELCPMH=1 mode, and 48KB is wasted. Note: The "MTX512 S2" badge appears on various peices of Memotech kit, including my special one-off system, later SDX systems, and even underneath the Videowall Controller badge on a videowall controller. So people will also refer to these other things as Series 2.
FDX, containing MTX motherboard (64KB RAM), FDX 80 column card, FDX disc controller card, one or two 5.25" disk drives, possibly an external unit with one or two 8" disk drives, possibly a FDX Silicon disc card, internal PSU. Ran CP/M 2.2.
8" disk drive unit for the FDX. Was basically the same size as the FDX case, but with one or two NEC 8" drives accessible through a hole in the rounded-rectangle end plate. These were the same kinds of drives as used in the SM1. Note sure if any were ever sold, I may have had the only one.
HDX, containing MTX motherboard (64KB RAM), FDX 80 column card, a disc controller card, a 5.25" disk drive and a hard disk, possibly an external unit with one or two 8" disk drives, possibly a FDX Silicon disc card, internal PSU. The normal FDX boot ROM and FDX disc controller only understands 5.25" and 8" disk drives, so I think the HDX must have had its own slightly different boot ROM and disc controller card. Ran CP/M 2.2.
HRX, which was basically an FDX or HDX, with a high resolution graphics card (at 256x256x18bpp). Ran CP/M 2.2. Had graphics package able to do basic image processing, such as sharpen, blur, scale, rotate, etc.. This was shown at trade shows, but I'm not sure any were ever sold.
FDX Single (perhaps also referred to as a single disc system). FDX case with FDX disc controller card and a single 5.25" drive. No 80 column card. Does not run CP/M - ROM 4 must therefore be a variation of the SDX ROM, except using the FDX controller card. Claus has one of these.
MTX with SDX (old version), and maybe an 80 column card. Had a SDX floppy disc controller card which plugged into the left hand side of the MTX, and an external 5.25" or pair of 5.25" drives. In principle, the SDX unit can drive 3.5" drives, although I don't think this combination was ever sold. This could be sold with the combined serial and 80 column card within the MTX case as a CP/M system. Or it could be sold without this as an MTX BASIC system with USER commands to access the floppy disk. With a small tweak to the hardware, it could have been possible for the CP/M variant to also act as a MTX BASIC system with USER commands. With the SCPM variant of the CP/M boot ROM, the 80 column card wouldn't have been necessary to run CP/M. Picture and this Advert courtesy of Jim Wills.
MTX with SDX (new version), and maybe an 80 column card. Had a SDX floppy disc controller card and a 3.5" disk drive. Both the card and drive were together in a single add-on, which was plugged into the left hand side of the MTX. Out of the box could support CP/M and MTX BASIC USER commands. To support CP/M either the 80 column card could be used, or an SCPM variant of the CP/M boot ROM could be used. The SDX had 512KB of extra memory which be used as RAM Disc, providing the OSROM on the motherboard is patched not to corrupt this memory during the startup memory test.
Videowall controller. Is basically an MTX with newer SDX with no 80 column card, using the SCPM EPROM. Might also include a 128KB ROM card, and use a CP/M boot ROM which initialised the RAM Disc from this ROM, thus avoiding the need to include the floppy disk drive.
Memotech Business/2. Had MTX motherboard (probably 64KB RAM), 80 column card, SDX floppy disk controller, a single 3.5" disk drive, amount of RAM unknown (probably motherboard plus 512KB), doesn't seem to have a VDP chip or video board, MTX serial card probably present, probably a modem card (visible top-left), internal PSU, all within a half-height FDX-like metal case. Booted B:7. Ran CP/M 2.2. Pictures from Marco in Italy.
Mentioned on the Memotech Videowall literature. In a half-height FDX-like metal case. One 3.5" floppy disk. New style SDX card, with RAM unpopulated. Motherboard upgraded to 256KB. ROM and RS232 card mounted at right-angles on right-hand-side. MTX keyboard attached through coiled cable. Picture courtesy of Dave Stevenson.
My own special special hybrid system, as given specially to me by Geoff Boyd. Has MTX motherboard (32KB RAM), SDX floppy disc controller with SCPM+SDX EPROM and 512KB RAM, a single 3.5" disk drive, MTX serial card, internal PSU, all within a half-height FDX-like metal case. Now upgraded to SDX Plus.
An add-on which allowed the MTX to run various ZX Spectrum games.

Picture	Description
	MTX500, containing MTX motherboard (32KB RAM), external PSU. You could optionally add the MTX serial card inside. Ran BASIC.
	MTX512, containing MTX motherboard (64KB RAM), external PSU. You could optionally add the MTX serial card inside. Ran BASIC.
	RS128, containing MTX motherboard and MTX RAM card (giving 128KB RAM total), MTX serial card, external PSU. Ran BASIC.
	MTX Series 2, which was like the MTX512, except that it had 256KB RAM directly plugged into it, a selection of yellow wires on the back of the motherboard, and an alternative address decode PAL. Usually only 64KB is visible in RELCPMH=0 mode to MTX BASIC. 208KB is visible in RELCPMH=1 mode, and 48KB is wasted. Note: The "MTX512 S2" badge appears on various peices of Memotech kit, including my special one-off system, later SDX systems, and even underneath the Videowall Controller badge on a videowall controller. So people will also refer to these other things as Series 2.
	FDX, containing MTX motherboard (64KB RAM), FDX 80 column card, FDX disc controller card, one or two 5.25" disk drives, possibly an external unit with one or two 8" disk drives, possibly a FDX Silicon disc card, internal PSU. Ran CP/M 2.2.
	8" disk drive unit for the FDX. Was basically the same size as the FDX case, but with one or two NEC 8" drives accessible through a hole in the rounded-rectangle end plate. These were the same kinds of drives as used in the SM1. Note sure if any were ever sold, I may have had the only one.
	HDX, containing MTX motherboard (64KB RAM), FDX 80 column card, a disc controller card, a 5.25" disk drive and a hard disk, possibly an external unit with one or two 8" disk drives, possibly a FDX Silicon disc card, internal PSU. The normal FDX boot ROM and FDX disc controller only understands 5.25" and 8" disk drives, so I think the HDX must have had its own slightly different boot ROM and disc controller card. Ran CP/M 2.2.
	HRX, which was basically an FDX or HDX, with a high resolution graphics card (at 256x256x18bpp). Ran CP/M 2.2. Had graphics package able to do basic image processing, such as sharpen, blur, scale, rotate, etc.. This was shown at trade shows, but I'm not sure any were ever sold.
	FDX Single (perhaps also referred to as a single disc system). FDX case with FDX disc controller card and a single 5.25" drive. No 80 column card. Does not run CP/M - ROM 4 must therefore be a variation of the SDX ROM, except using the FDX controller card. Claus has one of these.
	MTX with SDX (old version), and maybe an 80 column card. Had a SDX floppy disc controller card which plugged into the left hand side of the MTX, and an external 5.25" or pair of 5.25" drives. In principle, the SDX unit can drive 3.5" drives, although I don't think this combination was ever sold. This could be sold with the combined serial and 80 column card within the MTX case as a CP/M system. Or it could be sold without this as an MTX BASIC system with USER commands to access the floppy disk. With a small tweak to the hardware, it could have been possible for the CP/M variant to also act as a MTX BASIC system with USER commands. With the SCPM variant of the CP/M boot ROM, the 80 column card wouldn't have been necessary to run CP/M. Picture and this Advert courtesy of Jim Wills.
	MTX with SDX (new version), and maybe an 80 column card. Had a SDX floppy disc controller card and a 3.5" disk drive. Both the card and drive were together in a single add-on, which was plugged into the left hand side of the MTX. Out of the box could support CP/M and MTX BASIC USER commands. To support CP/M either the 80 column card could be used, or an SCPM variant of the CP/M boot ROM could be used. The SDX had 512KB of extra memory which be used as RAM Disc, providing the OSROM on the motherboard is patched not to corrupt this memory during the startup memory test.
	Videowall controller. Is basically an MTX with newer SDX with no 80 column card, using the SCPM EPROM. Might also include a 128KB ROM card, and use a CP/M boot ROM which initialised the RAM Disc from this ROM, thus avoiding the need to include the floppy disk drive.
	Memotech Business/2. Had MTX motherboard (probably 64KB RAM), 80 column card, SDX floppy disk controller, a single 3.5" disk drive, amount of RAM unknown (probably motherboard plus 512KB), doesn't seem to have a VDP chip or video board, MTX serial card probably present, probably a modem card (visible top-left), internal PSU, all within a half-height FDX-like metal case. Booted B:7. Ran CP/M 2.2. Pictures from Marco in Italy.
	Mentioned on the Memotech Videowall literature. In a half-height FDX-like metal case. One 3.5" floppy disk. New style SDX card, with RAM unpopulated. Motherboard upgraded to 256KB. ROM and RS232 card mounted at right-angles on right-hand-side. MTX keyboard attached through coiled cable. Picture courtesy of Dave Stevenson.
	My own special special hybrid system, as given specially to me by Geoff Boyd. Has MTX motherboard (32KB RAM), SDX floppy disc controller with SCPM+SDX EPROM and 512KB RAM, a single 3.5" disk drive, MTX serial card, internal PSU, all within a half-height FDX-like metal case. Now upgraded to SDX Plus.
	An add-on which allowed the MTX to run various ZX Spectrum games.

Unanswered questions :-

Why did MTX systems in Italy only use 480KB of the 512KB memory on the MTX RAM card? A limitation of the address decode logic perhaps? Perhaps the motherboard was only 32KB?
If an MTX512 S2 provided memory beyond the 64KB on a normal MTX, and an SDX was attached, did it have a different memory decoder ROM to avoid these memory ranges clashing?
What was the spec of the Russian MTXs, in the extra long red cases?

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