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I have several different Japanese 8-bit computers, and they use similar DIN connectors for video and cassette I/O:

  • Composite video: 180° 5-pin DIN: Fujitsu FM-7, NEC PC-8001mkII
  • Color TTL (digital) RGB/RGBI video: 8-pin 270° DIN: Fujitsu FM-7, NEC PC-8001mkII
  • Cassette: 270° 8-pin DIN: Fujitsu FM-7, NEC PC-8001mkII, NEC PC-6001

These are just ones I have examined myself; I have seen various other examples on the net that look as if they also output the above signals out the same jacks.

Is there a common (even if informal) standard for any or all of these, or do Japanese 8-bit computers frequently use the same 5-pin and 8-pin DIN connectors for these signals but with different pinouts?

I am interested just in the signals listed above: cassette audio, composite video and TTL (digital) video. (I believe that would restrict this mainly to pre-MSX and MSX1 computers.) Standards for the monitor side of the connection or analogue RGB signals outside the scope of this question, unless they have a direct bearing on the connectors/signals above.

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    msx.org/wiki/RGB_(8-pin_DIN_45326) answers some of the questions... – UncleBod Sep 6 at 6:55
  • @UncleBod Great link, thanks! Though I was really looking more for coverage of pre-MSX computers and RGBI, this is useful information. Particularly interesting is that the FM-X RGBI is almost, but not quite, the same as the FM-7 RGBI: the green and blue appear to be reversed. (But I've not verified that pinout on my actual FM-7 yet.) – Curt J. Sampson Sep 6 at 10:12
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    There's also the Sega SC-3000 with a 5-pin DIN for video, and its keyboard-less cousins with either 5- or 8-pin DINs including the SG-1000, the Sega Master System, and the Sega Genesis/Mega Drive. – snips-n-snails Sep 6 at 18:12
  • @snips-n-snails There's an interesting thing to bring in. Looking at the SC-3000 pinout here (note he's using non-standard pin numbering) and the 8-pin Master System pinout here it seems that those connectors are both "standard" composite with signal on 3 and ground on 2, though the additional RGB signals on the latter are analogue. – Curt J. Sampson Sep 6 at 19:16
  • Actually, my comment about the green/blue being reversed in the FM-X RGB is probably wrong; the diagram is inconsistent with the table on the MSX wiki, and the diagram is based on a source with a different pinout (and even number of pins!). I guess a test would be nice to see, but at the moment I'm going to go with the table. – Curt J. Sampson Sep 7 at 10:08
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Is there a common (even if informal) standard for these,

No, it has been different from the begining. Not even the ubiquitous MSX standard could establish a unified connector and even less a pinout.

In later years SCART/JP21 established a common use by market force, as it became a standard for TV sets in Japan and large parts of Asia. Still, compatibility was often reached by supplying a cable to connect a computers proprietary plug to JP21 required by standard monitors/TVs.

or do Japanese 8-bit computers frequently use the same 5-pin and 8-pin DIN connectors with different pinouts?

Not only that, but they use as well both versions of the DIN 45326 type 8 connector. 8A with 45° (als called 270°), but as well type B with 41° (sometimes marked as 262°) - like most beautiful of all MSX, the Yashica YC-64.

Mechanical it's down to two main connectors.

  • DIN 45326 type 8A
  • SCART/NFC 92250 (only the connector)

With the DIN next to all manufacturers had their own pinout. Some even changed between machines like Panasonic did. They not only differ in signals present (RGB or YUV, sync on green, separate sync, combined sync, ...), but as well in where they are placed (FM-X got +12V on pin 1, while Sanyo puts blue on 1).

The situation changed a bit after Japan adopted their version of SCART with the TTC-3/CPE-1201 standard. In Japan and Korea it's usually called/labeled RGB-21, while outside (Europe at least) JP-21 is the common name. While using the 21 pin SCART connector, the signal assignment is complete different.

De facto standardisation on the monitor/TV side happened in the mid 1980s, when Japanese (and later Korean) by default offered RGB (and later S-Video) input via JP21 connectors. In the late 1980s next to every Japanese home computer was sold either with a proprietary to JP21 cable, or newer machines already had JP21 build in, so standard cables could be used.

Note, that his is only true for machines for Asian markets. Units designated for Europe (like Sony HB-G900) had fully SCART compatible connectors on the back.

Bottom Line: JP-21 may be the closest answer here. It did, beginning in the mid 1980s, clean up the CRT side, but only in part replaced proprietary connectors on the console side. And it's not a DIN either.

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    Any non-DIN connections (particularly for TVs and monitors) are irrelevant to this question: I'm asking specifically about DIN connections, and mainly as they apply to early Japanese 8-bit computers. (If there are monitor standards that re-use the computer standards, that's a bonus, but if there are no computer standards, what the monitors use is irrelevant to me.) If you could provide examples of the computer connections being different, that would help improve your answer immensely. (And maybe also provide examples of 262° connectors on Japanese 8-bit computers, especially early ones.) – Curt J. Sampson Sep 6 at 12:56
  • @CurtJ.Sampson have the decency to appreciate what others do for you. Is it imaginable, that the combination of rudeness and at the same time asking for even more work to be done, isn't appealing? Especially when not even trying to read what has been given to you? – Raffzahn Sep 6 at 13:15
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    Sorry, I missed your note about the Yashica YC-64. Verbose answers with extensive information not directly related to the question can have value, but you can also expect that people will often miss small bits of information buried in them. – Curt J. Sampson Sep 6 at 13:53
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    FWIW, I think the question benefits from a narrowing of scope, which I have done. Feel free to update your answer accordingly if you wish, or suggest further changes to the question if it seems unclear or misguided. – Curt J. Sampson Sep 6 at 16:03
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[This is a community wiki post. However, if you don't have enough reputation to edit it, or just don't feel like doing the work, feel free to post a comment on it linking to the source of a pinout that's not yet here and I will add it to the post --cjs.]

This won't help with determining if there are any formal standards, but we can at least figure out if there are informal/accidental standards by looking at actual machines. MSX1 seems to be fairly consistent (excepting analogue RGB, which we're not covering here), so between that and the pre-MSX computers there aren't all that many of them. The listings below are in approximately chronological order of release.

In this answer we use the standard pin numbering, below looking in to the female jack on the computer. Note that some refrences are different, in particular some that give a numbering marked "male" are actually looking at the side of the connector you solder, which gives the same numbering as below. But check the reference carefully!

       ∪                 ∪
                      7     6
  3         1       3    8    1
    5     4           5     4
       2                 2

The critical signals to make the interface work are in CAPS below; "extra" signals that shouldn't harm operation if left unconnected are in lower-case.

Cassette

Verdict so far: very standard.

                     1      2      3      4      5      6      7      8
NEC PC-8001         GND    GND    GND    REC    PLAY   REM+   REM-   GND
NEC PC-6001mkII     cmt1   cmt2   GND    REC    PLAY   REM+   REM-   GND
Fujitsu FM-77       GND    GND    GND    REC    PLAY   REM+   REM-   GND
MSX Standard        GND    GND    GND    REC    PLAY   REM+   REM-   GND

Notes:

  • There are a few exceptions to the standard for the MSX CMT interface. Most of them use a 5-pin port, and so are obviously different. It's not clear if the Frael Bruc 100, a not-quite-MSX computer, uses an 8-pin port, but at any rate it's Italian, not Japanese.

Sources: PC-8001 CMT, PC-6001mkII CMT, FM-77 CMT, MSX CMT.

Composite Video

Verdict so far: two standards, one for non-MSX, one for MSX.

                     1      2      3      4      5
NEC PC-8001         ???    GND    COMP   ???    ???
Fujitsu FM-77       2MHz   GND    COMP   hsync  vsync
Sega SC-3000        audio  GND    COMP   gnd    gnd
MSX Yamaha/Victor   sound  GND    a/v+5  nc/rf  COMP           

Notes:

  • The MSX comp used by Yamaha and Victor may not be an MSX-defined standard. It's incompatable with other systems listed here. The a/v+5 is used as a control signal to JP-21 (and possibly SCART) connections to set the aspect ratio.
  • The Sega Master System/Mega Drive 8-pin video connector is also compatible with a 5-pin composite video cable using 2:GND and 3:COMP.

Sources: Sources: PC-8001 comp, FM-77 comp, SC-3000 comp, MSX comp.

Digital RGB Video

Verdict so far: very standard.

                     1      2      3      4      5      6      7      8
NEC PC-8001         vcc    GND    14Mhz  HSYNC  VSYNC  RED    GREEN  BLUE
NEC PC-6001mkII     14MHz  GND    ccont  HSYNC  VSYNC  RED    GREEN  BLUE
Sharp MZ-700        video  GND    csync  HSYNC  VSYNC  RED    GREEN  BLUE
Fujitsu FM-7        +12V   GND    2MHz   HSYNC  VSYNC  RED    GREEN  BLUE
MSX Digital         +12V   GND    n/c    HSYNC  VSYNC  RED    GREEN  BLUE
Sharp MZ-800        i      GND    unused HSYNC  VSYNC  RED    GREEN  BLUE

Notes:

  • The Sharp MZ-700 RGB scan has been corrected by hand to reverse the original 3:HSYNC and 5:CSYNC description, which was presumably a typo. The MZ-800 RGB source also gives an MZ-700 pinout that matches the correction.
  • Warning: The MSX RGB pinout above applies only to those MSX computers that use digital RGB ouput, which is very few (Fujitsu FM-X, Pioneer PX-7, PX-V7 and PX-V60 according to the source). Most MSX computers seem to use analogue RGB outputs on 8-pin connectors, which are not compatible with digital and vary in the pins they use for which signals.

Sources: PC-8001 RGB, PC-6001mkII RGB, MZ-700 RGB (p.19), FM-7 RGB, MSX RGB, MZ-800 RGB.

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There's a seller on Yahoo Auctions in Japan named michael_torojirou who makes cables for pre-90s computers. Over the last several years has sold a lot (several thousand, from the looks of it) of them with consistently good feedback, so it's likely that they work.

From his offerings for cables that connect 8-pin DIN digital RGB outputs to various kinds of monitors, we can see that the same cable is used for a wide variety of computers, indicating that these outputs are fairly standardized, even beyond the early 8-bit computers and MSX1.

Some examples:

MZ/PC-8801/8001/6001/6601/FM-7 to "RGB21" (i.e., the JP-21 variant of SCART). There's obviously digital-to-analogue RGB conversion circuitry in this cable because most of the computers he discusses have only digital outputs, and he's tested it with an analogue RGB display (Sanyo CMT-A14F1G) and several up/down-scalers. He lists this as usable with:

  • Fujitsu FM-8、FM-7、FM-NEW7
  • SHARP MZ-700/1500/2200/2500 (2500 at 16 colours, 15 KHz only)
  • Casio FP-1100
  • NEC PC-6001mk2、PC-6601/SR、PC-8001mk2/SR
  • NEC PC-8801mk2 series digital 8-pin ouput (8 colours)
  • NEC PC-9801 series digital 8-pin output (8 colors at 15 KHz low resolution)

MZ/PC-8001/6001/6601/FM-7 to DB-15 (not DE-15), for monitors with a 15-pin analogue RGB input. It seems basically the same as the cable above with a different monitor-side connector, and supports the same set of computers as above.

MZ/PC-8001/6001/FM-7三菱液晶MDT221WG/MDT242WG/RDT202WLM to DE-15. This seems to be for monitors like the Mitsubish [MDT242WG] that support analogue RGB at 24 kHz. It's been tested to work with:

  • SHARP MZ-700, 1500 (startup screen), 2500 (several games; 16/8 colours only)
  • Fujitsu FM-7, FM-NEW7 (several games)
  • Casio FP-1100 (startup screen)
  • NEC PC-6001mk2 (startup screen; PC60/PC66 16 colors not supported)
  • PC-8001mk2 (startup screen; 40-cols not supported)
  • PC-8801mk2FR (several games; 24 KHz)

He goes on to say that this is supposed to work with (I guess some) MSX2 computers and game consoles as well.

So it seems that there is a fairly standard pinout for digital RGB on 8-pin DIN connectors for early Japanese 8-bit computers.

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