USB Serial (Communication Class

05-03-2021 admin

USB communications device class (or USB CDC class) is a composite Universal Serial Busdevice class.

The communications device class is used for computer networking devices akin to a network card, providing an interface for transmitting Ethernet or ATM frames onto some physical media. It is also used for modems, ISDN, fax machines, and telephony applications for performing regular voice calls.

Microsoft Windows versions prior to Windows Vista do not work with the networking parts of the USB CDC, instead using Microsoft's own derivative named Microsoft RNDIS, a serialized version of the Microsoft NDIS (Network Driver Interface Specification). With a vendor-supplied INF file, Windows Vista works with USB CDC and USB WMCDC devices.^[1]

This class can be used for industrial equipment such as CNC machinery to allow upgrading from older RS-232 serial controllers and robotics, since they can keep software compatibility. The device attaches to an RS-232 communications line and the operating system on the USB side makes the USB device appear as a traditional RS-232 port. Chip manufacturers such as Prolific Technology, FTDI, Microchip, and Atmel provide facilities for developing USB RS-232 devices.

Devices of this class are also implemented in embedded systems such as mobile phones so that a phone may be used as a modem, fax or network port. The data interfaces are generally used to perform bulk data transfer.

References[edit]

^Support for the Wireless Mobile Communication Device Class

Usb Serial Communication Protocol

When 'USB Serial' changes to 'USB Serial (Communication Class, Abstract Control Model)' and a COM port number is shown, you can access your program on Teensy using that COM port. If there is no 'USB Serial' at all, please rememober Teensy only becomes a Serial device when programmed to do so. A google search for ACM reveals that it is part of CDC (Communications Device Class) which is a USB communication class opposite of HID (i.e. A USB device may use HID or CDC). This wikipedia articlereveals that CDC/ACM is a method of emulating RS-232 communication over USB. The USB port can be full or high speed. Device firmware manages USB communications and whatever other tasks the device is responsible for. Instead of a vendor-specific driver, the PC uses the USB communication devices class (CDC) driver included with Windows and other OSes. For Windows, an INF file matches the driver to the device. Universal Serial Bus Class Definitions for. January 19, 1999. USB Class Definitions for Communication Devices Version 1.1 ii January 19, 1999 Scope of this Revision This version 1.1 of this class specification is intended for product design. Every attempt has been made to ensure a.

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