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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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USB VCP connection fails occasionally

My question is quite simple: I operate 20 CP210x (Silicon Lab) devices over an industrial 20 Port USB Hub. In one of about 1000 trials to open the port I get a problem: The call to CreateFile(portName, GENERIC_READ | GENERIC_WRITE, 0, NULL,…
MichaelW
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Get COM port number of usb serial FTDI

I have a FTDI usb-serial and I am interested in the getting the COM port assigned to the device on USB serial converter A. Is there a way I can list this information programatically (say cmd) to extract the COM port number that corresponds to the…
rookie
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Adding driver for Prolific USB-RS232 PL2303 Converter to Linux Build for MYB-AM335X

I have an AM335X TI Development board which can be found here. I believe it is based on a Texas Instruments AM335X CPU module. I am using Buildroot to build the Filesystem for this board and I need to use USB-Serial converters. I know that FTDI…
Jadboy20
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Prolific USB driver on OSX 10.13

I'm trying to use the prolific USB driver on OSX 10.13, I've run the installer but can't get the computer to see the device. From the PDF it references USB Controller D, I don't have that, I've attached the screen shot. I can't even pass the device…
Cate Daniel
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Problems reading an `echo`, with the `cat` command in a serial port

I'm having problems sending an echo to an a RFID reader. In one terminal I'm running a cat like cat < /dev/ttyUSB0 and in another one I'm sending an echo like echo $'\x80\x80\x80\x01\x01\x01\x11\x14' > /dev/ttyUSB0, where the bytes are the command…
Aleix Vila
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STM32 based USB CDC firmware has not output in Linux

I am designing an IoT project with RF transceiver and OpenWRT. The RF transceiver has onboard STM32 micro, and it can be access in Windows as 'COMx'. I plan to use serial and socket module in Python to build a quick solution. But the device doesn't…
Allan K Liu
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Using usb-serial set rts to high

I am trying to implement this: https://github.com/mik3y/usb-serial-for-android/blob/master/usbSerialExamples/src/main/java/src/com/hoho/android/usbserial/examples/SerialConsoleActivity.java I have an LED connected to rts and 5v pin through CH340g.…
Muhammad Bilal
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USB-to-serial driver for Linux

I have a USB device that I need to control in Linux using Python and serial commands, it works with ASCII commands. In Windows it works fine after I install the vendor driver and in Device Manager I see it as a COM3 port and I communicate using…
betelgeuse
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Do I understand the mechanism of COM Port assignment for USB-Serial bridge (VCP) correctly?

I have to base a critical Windows 7 software on virtual COM Port assignment. The software has to test devices in a production line. Each device is different and needs to be supplied with individual security keys. There are 20 serial connections…
MichaelW
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Reading a Hex data array byte value from serial port

I have to read a data from Serial port using C program. I am sending Hex array data and the device will response the corresponding response for the request. I have tried with the GTK+ Serial port Terminal, For Example, if i write data "FC 05 40 2B…
sarvankumar_t
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Raspberry Pi issue: cannot create 4 SerialDevice objects with windows IoT Core

I have a project that requires a Raspberry Pi 3 to read 4 USB inputs coming from 4 microcontrollers (SAMD21G mini breakout boards in particular). They are connected directly via USB. Raspberry Pi 3 is running Windows IOT core. I have used…
marionR
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Is it possible to connect to an i2c device through a USB to RS485 serial converter cable on Linux?

I currently have a sensor attached to a USB to RS485 Serial converter cable which is plugged in to a raspberry pi. I've tried using the ftdi d2xx drivers to connect to it, but so far I can't read any data and while the writes don't fail, I'm not…
CSturgess
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Win10 USBSER Device Hardware Descriptors

I'm using USB Class02/SubClass02 on my embedded device to make use of the Windows10 build in USB COM port drivers (usbser.sys / mdmcpq.inf). My device provides manufacturer/device descriptors, but i have found that Win10 does not seem to use them as…
thecoder
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Python: serial communication with USB to serial converter failing

I am trying to write a code that talks with the serial interface using a USB to serial converter. I am running my code on a Ubuntu 12.04 OS. I have attached the device and it looks like it is recognized by the system, as the output of the lsusb…
toti08
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I cannot send data to my Arduino through usb serial connection

So, I have an arduino uno R3 SMD edition and I want to send commands to it while it's running. It has an adafruit v2 motor shield connected to it, which is powered separately from the arduino. The arduino is connected to my laptop by a usb…
Jacob
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