Strange cable

Not a RISC OS thing, but I acquired some assorted devices and cables recently and I’m trying to work out what a short (15cm/6") cable with a audio jack plug on one end (4 separate rings) and a USB A socket on the other could be. No markings, other than the USB trident on the socket end.

Any bright ideas?

Could be for an old style digital camera?
I had one many years ago that had a 3.5mm Jack to a serial plug to transfer images from an early Olympus digital camera.

I really have no idea. The strange thing is that it’s a USB socket, which usually means it’s the device that’s controlling the USB interface.

USB A socket? That’s rather odd. I was going to suggest a charging cable for some old device like a phone in the bad old days when everyone had a different connector, but that would have a plug. As would an active cable with over large plug having electronics in it (eg USB to serial).

But a socket suggests whatever widget is being a USB host, and that’s unusual.

Best guess is for some widget to talk to USB sticks, card reader or maybe keyboard/mouse. But for whatever reason they didn’t use a regular micro USB OTG port. Or maybe to allow one widget to charge another from a port that happened to have 5V?

Is there continuity between the USB data lines and rings on the jack?

At work we’ve seen some strange cables. USB A Male to USB A Male and selling on ebay 15pin HD D Type male (SVGA) to HDMI male, whilst the first could have a use, I can’t see any two pieces of equipment the could be connect via SVGA to HDMI, but cables like this do sell! I can only think the buyers think it will automagically convert analogue to digital or visa-versa and find out the hard way that it doesn’t. The worst cabling has been mains AC on plugs looking like DC.

Is there continuity between the USB data lines and rings on the jack?

Yes.

The tip and the second ring connect to the two data lines. The third and fourth rings connect to the outer two pins.

So it looks like a simple weird cable, no magic electronics, and it won’t be useful.

Cut in two before throwing away! We always used to get people salvaging cables from bins at work.

Do you mean like this thing?

https://www.cdiscount.com/informatique/composants-informatiques/3-5mm-male-aux-audio-prise-de-courant-jack-vers-us/f-107130605-sod0192948118265.html

Apparently one end goes in the AUX of a car radio and the other lets you plug in USB storage in order to play music.

It’s the first I’ve heard of 5V being on the audio jack. Sounds a bit iffy to me.

Our Honda Jazz has something equally weird for the radio.

A wired adapter (came with the car) plugs into a weird radio socket marked USB and then USB storage can be plugged onto the USB socket on the end of a 6" cable.

selling on ebay 15pin HD D Type male (SVGA) to HDMI male, whilst the first could have a use, I can’t see any two pieces of equipment the could be connect via SVGA to HDMI

Well…you ain’t seen nothing yet then. Those cables usually contain an active converter from HDMI to VGA – HDMI can power devices after all, so no principal problem here. And the “plastic blob” of a typical VGA connector has easily enough space for a tiny bit of electronics.

Not sure where the target market is though – ye olde big-screen backprojector devices or equally old CRT projectors are unlikely to be still alive…on the other hand, vinyl is also still alive, so maybe there is an avid Barco fan club somewhere. And maybe some old expensive projector installations where you can’t easily change the analogue cabling.

I am well aware of HDMI to SVGA and SVGA to HDMI ‘Active’ cables like this listing I’m thinking of cables like this I know some electronics can now be made very very small but am sceptical about this cable, the lack of details specs, resolutions supported etc. reinforces my belief.

I have somewhere a very strange portable LCD screen that was used by our photographers to enable them to show customers the photos that had just been taken on a digital camera, at slightly larger than postage stamp size.

The camera end was a typical 4-pole 3.5mm jack, but the other end was a USB A connector, despite having nothing to do with USB. Some Chinese factory just had a load sitting around and thought “that’s got four connectors, that’ll do”.

Do you mean like this thing?

It looks right, I don’t know if I’m willing to plug it into my car radio and a USB device into it to see what happens! Maybe an old MP3 player.

I suppose the radio’s socket could check if two points on the plug were electrically connected (i.e. not separate rings) before it tried powering the device, in case it’s an audio input. Something like that, anyway…

I am well aware of HDMI to SVGA and SVGA to HDMI ‘Active’ cables like this listing I’m thinking of cables like this I know some electronics can now be made very very small but am sceptical about this cable, the lack of details specs, resolutions supported etc. reinforces my belief.

Ah, they’re mentioning 1080p, what could possibly be a reason to be sceptical…apart from their “hey! with audio!” part along with throwing around senseless bandwidth numbers of course which somehow limits their credibility…

But the size is not an indicator, look at this one as an example of a cable that I know that works just fine. Because I tried it myself.

Steffen I’m impressed with your cable, it reminds me of the joke “The microcomputer company was so successful they moved into smaller premises!”