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Questions tagged [usbserial]

This tag is used for software related questions about using USB-to-serial Bridges and Adapters. Hardware adapters attach a peripheral with a DB-9 or DB-25 connector to a USB connector on a PC or other host. Software or virtual adapters are drivers in the host which create a COM port interface to a USB connection allowing software to open the virtual COM port to a device attached to the USB connector.

USB-to-serial bridges/adapters were originally developed as a way to connect a USB device to a PC or host without USB ports. These adapters were an alternative to the legacy DB-9, RS-232 COM ports (usually referred to as simply a COM port), which were standard on older PCs when USB was first becoming available.

More recently, the COM port interface is being phased out of the PC industry in favor of USB. These adapters allow a user to connect a device requiring the legacy COM port to a desktop computer or laptop via one of its USB ports.

When connected the adapter appears on the computer as a Communications Device Class (CDC) USB device, more commonly known as a virtual COM port.

Some software applications designed to communicate with devices through a COM port may require a software virtual COM port driver to allow use with a USB connected device. In some cases such drivers must be installed and in some cases the operating system already has the drivers and when the device is connected, a virtual COM port will automatically be created.

An example of such an application is the Arduino IDE which is used to create a sketch for an Arduino or ESP32 microcontroller. The microcontroller is attached to the host with a USB cable which provides power to the device as well as a communications path. The user selects the virtual COM port created when the device is physically connected in order to download a program.

Generally speaking, a USB-to-serial bridge more specifically refers to the embedded technology, or microchip, within the hardware adapter that performs the actual logic and protocol translations between USB and generic asynchronous serial communication (UART or SCI).

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Logic to recognize the name of the COM port to which a USB to RS422 connector is connected (for Windows application))

I have an application where I am writing data to the serial port via an USB to RS422 convertor. This convertor cable to connected to my PC through an USB hub. The problem I am facing is that each time I change the PC in which I am running the…
vik22
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USB to serial adapter for full duplex communication

I have a modem with a serial port but my PC does not have a serial port. Hence, I bought an adapter like below picture. Once the modem switch to transmit mode, it can send something but it could never switch back to receive mode and its data light…
Ricardo Cristian Ramirez
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USB UART speed is wrong

The GUI on the PC sends a set of bytes to an embedded system. Bluetooth adapter, all fine USB cable, all wrong. Device is a FTDI USB TTL Serial Cable (vendor's product page here) We need a predictable speed. I send out one thing from the PC, but…
User.1
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How to use android USB port to serve as Host?

I have a Gingerbread Android phone (I'm talking for all v2.3 phones so make and model isn't a choice) Presently I'm trying to interface it with a USB to TTL/serial converter that would further sent the data to some device (out of scope). So are…
user1448559
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FTDI d2xx android communication

I've been trying to use TN_134 FTDI Android D2XX Driver and the test application, and failed miserably. LogCat tells me that it unable to load the .jni file and the app crashes every time it tries to... The .jni library cannot be loaded, because my…
TibiG
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Read USB data and display in browser

We have a USB scale that sends very simple binary data for the weight of whatever is on it. We want to auto-populate this data on a web form. Some work will be required on translating the bytes into a decimal number. What programming language…
Gareth Foster
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Serial number of the usb on windows Ce 6.0 in c#

I need to get the serial number of a usb stick connected to a windows ce 6.0 device. I tried with KernelIoControl and i get the serial number of the window ce 6.0 device but not the usb connected to it. private static string GetDeviceID() …
user1788654
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Serial Port read() gets only less bytes at a time

Operating system : Ubuntu Serial Ports Using : USB->Serial adapter (prolific PL2303) I have a sample serial port read and write programs. While running the applications,I am trying to send 4100 bytes ,write program able to do it in single shot. n…
Arun
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System.IO.Serial

I have a usb device that is supposed to send a number when queried. The instructions I have are: Connect the USB port to a PC and then open the virtual serial port at 9600 baud, 8 data bits, no parity, 1 stop bit. Send ESC (I think it's char…
WCoaster
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how to connect to specific RFID usb device in C#

I have a RFID device it connects to pc via usb(serial port or com) and sends data how can I get name of the port it connected? and how can I get it's data?(it sends 16 bytes in hex format ) I wrote this code in c# but, it doesn't work! var sp = new…
mahya sj
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USB to Serial emulation

I bought this magnetic strip reader writer (MSRE106) and I use USB adapter to connect it to my laptop because I have no serial port in my computer. But now I have a problem since the software of the device recognizes only serial ports on windows.…
bhappy
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Handling handshake lines in RS232 DB9 using rxtxComm

I used rxtxComm to communicate(send and receive data) with Arduino (USB-Serial port). How do i handle the handshake lines like DTR using the rxtxComm library? Can you give me some tutorial on this or some sample code??? Note: I use win7 OS. I…
Rps Deepan
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USB Clear Endpoint Feature

I am developing CDC driver for USB device and I stumble on some problem. The driver I am using on windows side uses Clear endpoint Feature as some kind of flish mechanism or to get data right. That causes me a lot of trobule because I cant get it…
CrazyChris
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Error opening serial USB port for communication

I am trying to establish communication with electrical test equipment for remote control and data logging with a python script. I am unable to even get off the ground. It looks like I am unable to open the port? Any help is appreciated. I am on a…
Aaron Vaughan
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How to make connection using cable USB to RJ45 serial connection in android

I have to make connection between machine and device via Rs232 protocol but I am facing problem in connection. When we are making connection from cable we didn't get any status like cable is connected or not, also not getting any alert popup for…
Nikhil Jogdand
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