Does this RS232 Serial Cable require an external Power Supply?

0

I have a device that supports USB and RS-232 protocols but the device comes with only USB cable. The device works just fine with USB cable, however, I need to use the RS-232. I've purchased RS232 Serial Cable 7FT RJ45 to DB9 but the problem when I plug it, my device is not powered on. These are pictures for the cable

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I just wonder, does the cable require an external power supply? As you can see from the first image. There is no info regarding this issue at the manufacture's website.

CroCo

Posted 2017-05-30T21:20:50.047

Reputation: 161

This is a very specific cable for a very specific bar-code scanner. Is your "device" the specific scanner? apparently yes. RS-232 is not providing any power. Something to power your "device" is needed. – Eugene Sh. – 2017-05-30T21:23:41.990

@EugeneSh., yes. I'm developing Barcode Laser Scanner application and my laptop doesn't have RS-232 port. I've purchased USB-to-Serial Port adapter (i.e. male cable) though but got stuck with this cable. What is the proper adapter to power it on? – CroCo – 2017-05-30T21:27:33.383

The rj45 end presumably plugs into your scanner. Since it's the only lead going to it it must provide power. The dc jack is located on the DB9 end so you just have the one cable running to the scanner, which is pretty clever. What voltage does the usb cable provide to the scanner? Perhaps it's a clue? – None – 2017-05-30T21:29:41.600

The clue is on the Amazon site link provided under "Frequently bought together" – Eugene Sh. – 2017-05-30T21:31:30.297

Why do you need to use rs232? Most of these scanners can be programmed over usb. – cde – 2017-05-30T21:36:17.207

@Passerby, because in USB case, the device works just as keyboard which means the cursor must be placed in a widget that accepts text however, with RS-232, I need only to monitor the port, more convenient and faster to scan several items. – CroCo – 2017-05-30T21:50:06.520

@CroCo - details would differ by operating system, but you could grab the USB device with a lower level API and get the data directly without it being treated as an everyday keyboard. It's also possible that you can readily adapt a USB cable (less data lines) to be the power source for this serial cable - though that would depend on the actual input voltage requirement. – Chris Stratton – 2017-05-30T23:39:12.353

Answers

1

You can pretty easily see, in the following picture (gathered from here), how power is applied:

enter image description here

Your first picture confirms the above approach, I think. You will need an appropriate wall-wart for it.

jonk

Posted 2017-05-30T21:20:50.047

Reputation: 126

Thank you for providing this picture. May I ask where did you get it? – CroCo – 2017-05-30T21:57:22.813

1

@CroCo Sure: http://www.thebarcodewarehouse.co.uk/Assets/Documents/Motorola/Manuals/Motorola-LS1203-Quick-Start-Guide.pdf

– None – 2017-05-30T22:08:06.733

1

Standard RS-232 doesn't carry any power as USB does. You'll need to power the scanner separately in this case.

JRobert

Posted 2017-05-30T21:20:50.047

Reputation: 6 128

Asked: 2017-05-30T21:20:50.047

Viewed: 2 136 times

Active: 2017-05-31T17:24:10.907