Bluetooth Serial Adapter

I found this on Amazon. DSD TECH SH-B23A Bluetooth 2.0 to RS232 Serial Adapter with DB9 Converter. The pictures in the Amazon listing didn’t show jumpers. Some sites say you need to hold the switch while powering up others just change the jumpers ahead of time. I think it depends on what hardware DSDTECH actually ships you.

Software to set the baud rate can be downloaded from DSDTech-Global

Manual for the device.

Set the baud rate. For me I connected a serial adapter to the serial port on SH-B23A and set BAUD to 9600 and com port to 7 and selected the tab for HC-05 in the software. Set the jumpers to PC and powered up the SH-B23A then pushed the micro-button and the DSDTECH tool software would get an ok when I sent an AT command. There is going to be some trial and error here. When done move the jumpers back to Device for connection to a switch or whatever you are using. I have two of these and just set one at 115200 and the other is left at 9600 as those are the most common settings for me. Default connection in the software is 9600 mine below is set to 115200. The DSDTech website says to use HC06, mine worked with HC05 and failed with HC06.

Button if needed

Remember to switch the jumpers from “PC” back to “device” after changing baud rate.


If you don’t get an “OK” after pressing “test”, you’re not connected to your computer. And even though it looks like you are changing the device parameters in the software, you are not. Worse, You will still be able to “connect” or “pair” via blue tooth with another device, but the baud rate likely won’t be correct (because you never actually changed it) and it will be connected via blue-tooth, but it won’t work (ie will not transmit data).

I used Windows 10 for my setup, may not matter.

Connected to the USB port on the front of a Cisco 3850 works well for power.

I am going to cut some holes in the case so I can press the micro button and move the jumpers without taking out the screws. Just need to use tweezers and something like a paper clip to push that button. I ended up not using the top half of the case.

I missed on the first attempt and had to drill a second hole.

Instructable with setup information. Another version with slightly different setup steps.

DSD TECH SH-B23A Bluetooth 2.0 to RS232 Serial Adapter with DB9 Converter

Amazon picture is different than what I get when I order, but what I have works fine.

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