DSD TECH SH-U09C2 USB to TTL Adapter Built-in FTDI FT232RL IC for Debugging and Programming

I liked the ease of operation

Im an embedded software engineer, reverse engineer, remaker and Voider of Warranties. Theres a 95% chance that any electronic device I obtain will be subjected to a teardown, a full gallery of explicit high resolution images taken of every nook, cranny and IC marking and datasheets obtained for as many components as possible. Thanks to the ubiquitous UARTs found in many embedded systems, from cameras to routers to electronic cigarette rolling machines (seriously. Its even got silkscreen labels!), thats often my first point of attack when I see a likely UART connection. The first step is determining the logic voltage levels used by that particular uart since 1.8V, 3.3V and 5V are all common(3.3V being most common) and its not a great idea to mix voltages when connecting to a devices I/Os so you want to be sure your USB UART adapter is using the same voltage as the UART. I used to either remove the USB uart adapter when I was done torturing a device or modify the device case to make the USB connector accessible and permanently install the USB adapter inside the case. The problem with that is that most of these adapters have a USB A male connector which means I either have to desolder it and replace it with USB B micro or mini so I can plug a regular device cable in when needed, or I have to use a USB extension cable which I dont tend to have many of and those I do have are either in use or are hiding with my missing left socks and sanity. So instead I started installing stereo headphone jacks so that the 3 conductors of a standard stereo plug can be used to carry GND, TXD and RXD. Those jacks are easy to install using just a drill and pliers, are reasonably cheap while providing a simple, unobtrusive and stable serial port. I only had to make a stereo headphone plug adapter that plugs into the GND, TXD and RXD pins on the USB adapter and set the logic level jumper to the correct voltage for that devices uart (I write it on a label next to the headphone jack on the device case since Ill never remember what device is what voltage). The only caveat is that you only want to insert or remove the headphone plug when no power is being applied to either the device or the USB adapter. This is because when youre inserting the plug, the different sections of the plug, each of which corresponds to one of the UART lines, can make contact with one or more of the contacts inside the jack until the plug is fully inserted. If youve ever plugged headphones or speakers into a live audio jack and heard a buzzy sounds until it was fully inserted, thats the same concept except with signals that can handle being shorted, at least for a short time. UARTs arent generally that resilient to such abuse so always disconnect the USB adapter from your computer and disconnect power from your target device before you insert or remove the serial jack. Then double-check that your USB adapter is set to the right voltage and you can plug that in to your PC and power up the target device. There are plenty of USB adapters that have 1 fixed logic level, often 3.3V. Theres nothing wrong with them other than being useless for other logic level UARTs. I have over a dozen different USB uart adapters with different chipsets, different logic levels and different connector types (and pinouts) for connecting to a target device. Most of them are 3.3V cheapo boards I got from China in bulk and probably arent even legit chips. More than 1 of them has died suddenly, started behaving erratically or in 1 extreme case had an internal short in the IC that popcorned the packaging and blew the fuse on my USB port(luckily it was just a hub). Thats why I decided it was time to standardize my serial ports and use only high quality USB adapters that can be configured for any of the 3 common logic levels as needed. If I had gone with a 4 conductor 3.5mm jack and plug, I could have added a wire for the Vio logic level from the device and had the plug route that conductor to the Vref reference voltage that the USB adapter uses for determining the logic levels to use. Instead I just use this USB adapter which has a 1.8V and a 3.3V voltage regulator to generate those reference voltage from the 5V USB power. Setting the jumpers just connects the output of the corresponding vreg to the FTDI chips Vref input. This is actually the ideal way to do it since the vregs should produce an accurate, stable reference voltage which might not be the case if it came from the device. Anyway, I couldnt ask for a better solution than the one this product provides. Not only is it well made with quality components and a solid design but it also exposes the additional pins of the FTDI chip such as those for hardware flow control and the user-configurable GPIO pins (theyre just unpopulated through-holes but easy to solder on some pins). Even the packaging is very high quality and professional. A++ for DSD Tech!

There are a lot of serial to usb adapters on the market, but I really like this one and have purchased several of them for use at home and at work. The ability to select several different voltages for the interface using a jumper allows you to use the device in various situations. Very nice physical presentation and easy to configure and use. Highly recommended.

Contrary to other chips that alias baudrates on a fixed selection, this one honors the requested baudrate. This is really important for using debugwire successfully on AVR microcontrollers for example.

I like the multi TTL levels as I have many 1.8, 3.3 and 5V devices and I can use this one adapter on them all. I also got a USB A female to Micro female so I could keep the TTL lines as short as possible.

I used this successfully to program new firmware on the Sonoff switches. Check out videos on YouTube on how to use it. It takes a few steps. But, it is a manageable process

Very good quality. In my opinion, the build quality of this product is better than the 20 bucks Adafruit one. And it provides 3 voltage configurations, which allows me to debug my 1.8V boards. It comes with female to female jumper wires, no need to buy wires seperately. The only caveat is that I need to purchase a USB extension cord.

Works as expected. Decent documentation.

One of the nicest USB<->TTLserial adapters Ive seen. Solid FTDI 245RL silicon and level shifters for 1.8 (!), 3.3, and 5V. Helped me to debug an issue with a development board. Thanks for a great product, DSD TECH. I ordered two more...

No hassle plugged right in win11 ready to use.