4

While going through some (really) old computer parts I came across a very interesting cable: a female RS232 (9-pin serial) to 3.5mm stereo jack.

Any ideas what this cable might have been used for? (it's not a makeshift DIY cable)

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I remember having an old Fritz ISA > ISDN card using a RS232 to RJ45 connection.

Gareth
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6 Answers6

7

Some devices (such as graphing calculators) use 3.5mm jacks to transmit data. They use similar signals to normal serial ports, but use a different connector.

3

Here's one use I found online: RapidRun DB9 to 3.5mm Adapter

Cable image

Quote:

Eliminate the need to run all new cables for RS-232 control of your Audio/Video system. RapidRun's new RS-232 Adapter gives you the flexibility to use existing 3.5mm stereo audio cables or DB9 cables to run 3 conductor RS-232 control signals between your control unit and your video display. This product can be used with all of the DB9 Break-Away Wall Plates and Flying Leads designed for the RapidRun system. RapidRun RS-232 Adapter Features: Supports transmission of serial control signals including RS-232. Fully molded DB9 and 3.5mm connectors provide excellent strain relief. Ideal for use with computers, projectors, and any control unit/display requiring 3 conductor RS-232 serial control. Note: Not all serial control methods are supported by this adapter. This product is intended only for use with 3-wire RS-232 control cables with common ground (pin 5), transmit data (pin 3), and receive data (pin 2). For the exact pinout of your audio/video equipment please contact the manufacturer.

Gareth
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Chris W. Rea
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2

I found a cable like this too, and finally figured it out that it came with my old late 1990s Olympus D-360L digital camera. It was used to transfer pictures to the computer (before card readers became common) and as I recall it would use a lot of battery transferring the pictures.

Dave G
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2

They are typically used as a pinout for digital cameras.

2

There are some devices (like say a RAID box I have at work) that use a 3.5mm jack instead of a standard 9 pin port to access their built-in console.

Chealion
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1

since you only really need three lines to do serial communication (and in this case we are not using hardware flow control, which would require two extra lines), a DE-9 to stereo jack is all you need for serial communication with anything with an embedded microprocessor.

The two cases I've used this are a serial programming cable to a TI cable modem, so you could get boot messages and command line access for firmware upgrade purposes; and a OneTouch UltraMini Glucose meter. Here the parent company will sell you an overpriced cable just so you can download your timestamped historic testing data into their "free" software app.

232rs
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