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can somebody please explain what is the relation between those terms. I tried to find some info in wikipedia, but there is no word about relation between those technologies, thanks in advance for any good abstraction or link

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Those 3 items are very different. What is it that you are trying to do? – Kellenjb Sep 30 '11 at 20:13
I'm trying to understand! thanks for -1, whoever You are – geek Sep 30 '11 at 20:17
I know the question may not be up to our "normal" technical standard, but how is a novice supposed to learn if he doesn't ask questions? – Majenko Sep 30 '11 at 20:23
@Kellenjb Actually while the technology is different they can be used toward the same application: loading and debugging programs onto your target hardware which is probably where geek is going ultimatley. – spade78 Oct 29 '11 at 19:07
up vote 7 down vote accepted

The only thing relating these three phrases is that they all have something to do with serial communication.

A "COM port" is a serial port specifically in Windows or DOS. They are the only operating systems which refer to serial ports as COM.

JTAG is a serial programming / data access protocol designed for interfacing with microcontrollers and similar devices.

A UART is a chip or sub-component of a microcontroller which provides the hardware to generate an asynchronous serial stream such as RS-232 or RS-485.

The "COM Port" and "UART" are probably the most closely linked in that a UART will be used in the computer to provide the hardware that Windows sees as a "COM Port".

The JTAG is completely unrelated.

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thank You for understanding me :), this answer was very important for me – geek Sep 30 '11 at 20:35

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