Model:SH-UR01A

Ok this is not a relay simply "on" when USB power is applied. The relay is controlled "ON/OFF" using serial commands, as many have already stated. I had no driver issue, as windows already had the driver - probably due to me installing many multiple devices in the past. I however wanted a simply Windows command line to turn the relay on or off. After lots of searching I made a batch file to simply turn on (or off) the relay. For those of you not wanting to use terminal programs, here is how I'm doing it through windows command line: (for the below ,the COM port my relay is installed to is COM8) 1st set the com port speed/info >mode COM8 BAUD=9600 PARITY=n DATA=8 2nd send the command >set /p x="AT+CH1=1" <nul >\\.\COM8 to turn it off, send the same command in line 2, but with AT+CH1=0 (not AT+CH1=1). I dont think you need to set the mode every time, but I put the 2 lines in a batch file just in case. So far its working exactly as I need it to. I made 2 batch files (1 for on, and 1 for off). Hope this helps someone.

I do like it's simple operation but some might have trouble trying to communicate with it because the commands must be sent as a complete string, not one character at a time. A program like Putty didn't work for me when trying this out on windows but look for a program called Realterm, it lets you set up commands that can be sent with a click of the button. Commands: AT response OK a test to see if the device responds AT+BAUD=? response OK+BAUD=9600 AT+CH1=? response OK+CH1=0 or OK+CH1=1 depending on the current state of the relay AT+CH1=1 response OK+CH1=1 this closes the relay AT+CH1=0 response OK+CH1=0 this opens the relay Some things that might help somebody... I have this plugged into a machine running Ubuntu 20.04.6 The device is accessed at /dev/ttyUSBn where n is a number. The number n can change with reboot of the system. In a terminal you can list devices with "ls -l /dev/ttyUSB*" To get information about each of the devices listed, I have two for example /dev/ttyUSB0 /dev/ttyUSB1 Use command "udevadm info /dev/ttyUSB0" to get a bunch of info that will help you identify which is the relay, mine for example shows ID_SERIAL=Silicon_Labs_CP2102N... The relay might not respond due to permissions, you need to add your user to the dialout group then you will have access to communicate with it. You will need to "initialize" it I guess, sometimes after reboot it seemed I needed to do it, sometimes maybe not, but I do command "stty -F $1 9600 cs8 -cstopb -parenb" then I can communicate with it. If you want to test it from the command line and see the response, I use something like this for example if my relay is connected at /dev/ttyUSB1 then I use: echo -ne 'AT+CH1=?' > /dev/ttyUSB1; read INPUT < /dev/ttyUSB1; echo $INPUT That would be the command to show the current status of the relay, substitute other commands as needed, that should execute the command and display the response. Using the various linux commands I listed above, I wrote scripts that read the list of devices to create a list of those that are /dev/ttyUSBn and then for each of them use the other commands to get their speed and id_serial so I know which device is at each of them, then initialize them, and shell scripts that take the port name as an argument and execute the relay_on and relay_off commands. Hopefully someone finds this information useful.

Bought this to replace a different USB relay that quit working after a month. PLUSES: +Plastic housing. No worries about shorting out the bottom of the PC board. So often you get a circuit board with NO mounting holes or other way to support it. +Wonder of wonders, IT SHIPS WITH A USER GUIDE! ON PAPER! What a concept! Minor gripes: -The housing on this is a little bigger than it needs to be. -The user guide makes no mention of the timing constraint for inputting control strings. Likely a lot of the reviews saying it doesn't work were a result of that. If I hadn't seen the reviews taking about the timing, I'd would have probably returned this. -It's a little weird for this to very loosely be emulating the old smart modem AT command set, but then trading away carriage return to terminate commands and using timing instead. The gripes are pretty minor vs the pluses. I hope this one lasts.

I can't be more satisfied. My situation, I have led tv backlighting and they have their own remote to turn off/on but I didn't want yet anothe remote so I used this to turn the led lighting's power supply off/on when the tv is turn off/on. Thus the led lighting uses my tv 📺 remote toturn off/on thru the usb port. It works flawlessly. U can't beat it for $10. I personally think the makers of the freakin led backlighting system should have done this in the 1st place but the didn't. And the led backlighting unit I got is the "best seller"on the market today. If anyone else has this problem, THIS IS UR ANSWER to one less remote and a more "intuitive" audio/video system. I hope u can use this unit like I did. Again it works flawlessly.

I thought I was buying a usb controlled relay. Nope. It’s a relay. On or off. Not complicated. But you have to download some drivers, ok not hard. But then while the computer sees the usb device, it doesn’t do anything. I hooked up a meter to the output of the relay and nothing. No switching. Power and no power to the usb side and no change to the relay.

Been using it for some industrial prototyping, works well enough the interface for it is a bit weird, but once you figure it out its not too bad. Works out of the box with my unusual FreeBSD setup so that's a win. My only major complaint is the documentation is not great. Basically amounts to looking at some pictures in on the product listing, and I still haven't figured out the specs on the 'input' terminals. Having a pdf that just lists out the specs, the API, etc on the manufacturer website would go a long way to answering technical questions.

I purchased this product and had some trouble getting it to work. I went to DSD-tech support and they replied in less than one day with a python program that operated the relays. A few bumps in getting started but 5 stars for OUTSANDING support. after support responded i was up and running in less than 30 minutes. phil

It does what it says it does; the instructions in the description of the product work just fine. I did have to install a driver - they should really just give a link to one (if they did, I didn't see it). I had to search for the chip driver - CP2102N, which came up with a generic CP210x driver that worked. I like that it comes enclosed - that puts it a step above the others, unless you're a hobbyist that has small project boxes lying around. I don't like using these sorts of things un-enclosed. I've written a C# "USB Relay Controller" that can control multiple brands/types of relays, and am including a screenshot of the code used to generate the byte string to output to turn on/off (or, more correctly, close and open) the relay.