Converting internal SCSI emulators to external use

[bigmessowires]

I have a couple of Zulu SCSI devices with the 50-pin IDC connector for internal use. It would be handy if I could temporarily convert one for external use. This adapter designed for SCSI2SD would seem to be exactly what I need...

50pin IDC female to SCSI-1 DB25 Adapter

This adapter allows ZuluSCSI and SCSI2SD devices with a male IDC50 connector to be used externally, adapting it to DB25F

store.rabbitholecomputing.com

...except it has a female DB25. But the Mac's exterior SCSI connector is a female DB25, so shouldn't the adapter have the male version? The product listing also doesn't show or specificy the gender on the IDC50 side, so I'm confused and I'm probably missing something. I tried searching specifically for a DB25M-to-IDC50F adapter, but came up empty-handed.

 

[Phipli]

I have a couple of Zulu SCSI devices with the 50-pin IDC connector for internal use. It would be handy if I could temporarily convert one for external use. This adapter designed for SCSI2SD would seem to be exactly what I need...

50pin IDC female to SCSI-1 DB25 Adapter

This adapter allows ZuluSCSI and SCSI2SD devices with a male IDC50 connector to be used externally, adapting it to DB25F

store.rabbitholecomputing.com

...except it has a female DB25. But the Mac's exterior SCSI connector is a female DB25, so shouldn't the adapter have the male version? The product listing also doesn't show or specificy the gender on the IDC50 side, so I'm confused and I'm probably missing something. I tried searching specifically for a DB25M-to-IDC50F adapter, but came up empty-handed.

Just use it with a Zip drive cable. That's what I do. I use that combo along with a Molex PSU to test hard disks without an enclosure.

 

[Skate323k137]

Just use it with a Zip drive cable. That's what I do. I use that combo along with a Molex PSU to test hard disks without an enclosure.

Yeah, DB25 cable and an adapter is what I do as well.

 

[bigmessowires]

Do you think any straight-through DB-25 cable would work, or does it need some extra shielding voodoo for SCSI? How about https://www.ebay.com/itm/293513211927

 

[jmacz]

FWIW, the larger ZuluSCSIs (ZuluSCSI 1.1 and ZuluSCSI RP2040) were ready for a DB25 connector soldered onto the PCB. I think the compact versions didn't though.

 

[stepleton]

It's off-topic and very "that guy" of me, but did I just come from the Berenstein Bears universe or is calling what the ZuluSCSI has an "IDC" connector a fairly new thing? To me it's a "header connector", 50-pin, two-row, shrouded in the ZuluSCSI's case. ("Header connector" or "pin header" or "SCSI header" also works here.)

IDC is "insulation displacement connector", which is to say those little pinchy knives that let clip-on headers and D-sub connectors bite into ribbon cables or other kinds of wires. On circuit boards there is no insulation being displaced in this way. If there's no ribbon cable to be found, "IDC" just sounds weird to me.

I heard Action Retro and also Noel from Noel's Retro Lab (both youtubers) call board-mounted headers "IDC" connectors recently, and here is another case. I couldn't recall hearing that usage before, so I wonder if it's new.

 

[cheesestraws]

It's off-topic and very "that guy" of me, but did I just come from the Berenstein Bears universe or is calling what the ZuluSCSI has an "IDC" connector a fairly new thing? To me it's a "header connector", 50-pin, two-row, shrouded in the ZuluSCSI's case. ("Header connector" or "pin header" or "SCSI header" also works here.)

I can't tell you the history, but I know I've been using it for ages - largely because 'two row pin header, 50 pin, 2.54mm, shrouded, keyed' is such a long phrase for such a small component, especially when I'm specifying something that is directly intended to mate with an IDC sensu stricto. I think this is just a natural process of language where a narrow subset of a broad class of thing becomes common in its own right (in this case, IDCish board connectors against headers as a whole) - one wouldn't, after all, specify a chicken by saying 'it's a bird' followed by listing all its phylogenetically relevant characteristics, one would just say "chicken". Even, say, an evolutionary biologist will refer to it as a chicken unless they have a reason to be more specific.

IDC is "insulation displacement connector", which is to say those little pinchy knives that let clip-on headers and D-sub connectors bite into ribbon cables or other kinds of wires. On circuit boards there is no insulation being displaced in this way.

Again, I think the relevant process here is a linguistic one, not an engineering one. English doesn't really distinguish between attributes that define something and those that describe something - even the distinction between 'that' and 'which' is basically dead in the spoken language in many speakers. So the distinction between "a connector that displaces insluation" and "a connector that is relevant to other connectors that displace insulation" is something that the grammar is very poorly served to represent - and so they end up sounding the same.

(edit: sorry, @bigmessowires, for the thread derail! Agree with people above who say that it's to use a zip-style cable. I've had luck with cheap 25-pin D-type gender changers of the kind one in multi-packs - or you could probably mount a male 25-pin d-type on the adapter board upside-down? Parallel-type 25 pin cables will only work if you're lucky, they're often made extremely cheaply. It doesn't matter so much for the gender changers because the distance is so small)

 

[pfuentes69]

I have a couple of Zulu SCSI devices with the 50-pin IDC connector for internal use. It would be handy if I could temporarily convert one for external use. This adapter designed for SCSI2SD would seem to be exactly what I need...

50pin IDC female to SCSI-1 DB25 Adapter

This adapter allows ZuluSCSI and SCSI2SD devices with a male IDC50 connector to be used externally, adapting it to DB25F

store.rabbitholecomputing.com

...except it has a female DB25. But the Mac's exterior SCSI connector is a female DB25, so shouldn't the adapter have the male version? The product listing also doesn't show or specificy the gender on the IDC50 side, so I'm confused and I'm probably missing something. I tried searching specifically for a DB25M-to-IDC50F adapter, but came up empty-handed.

I used this one for the BlueSCSI V1

GitHub - Stephen-Arsenault/OverEasy: A low-profile SCSI adapter from male 50-pin to male DB-25

A low-profile SCSI adapter from male 50-pin to male DB-25 - GitHub - Stephen-Arsenault/OverEasy: A low-profile SCSI adapter from male 50-pin to male DB-25

github.com

No idea if it would physically fit in a ZuluSCSI

 

[cgp]

Do you think any straight-through DB-25 cable would work, or does it need some extra shielding voodoo for SCSI? How about https://www.ebay.com/itm/293513211927

Yup. I use a ribbon cable:

 

[bigmessowires]

It's off-topic and very "that guy" of me, but did I just come from the Berenstein Bears universe or is calling what the ZuluSCSI has an "IDC" connector a fairly new thing?

It's the mating half of the IDC connector on the SCSI ribbon cable, so it seems natural to me to also call it an IDC connector. You're right that its not strictly correct, though. FWIW I also use the same terms when talking about floppy drive connectors, to distinguish between the 19-pin D-SUBs and the 20-pin ribbon cable rectangular connector.

 

[sfiera]

To me it's a "header connector", 50-pin, two-row, shrouded in the ZuluSCSI's case. ("Header connector" or "pin header" or "SCSI header" also works here.)

Slightly different meanings, in the way I'd use them. IDC implies shrouded and keyed. IDE uses 40-pin IDC headers; an RPi merely has a 40-pin pin header.