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The basic answer is yes: UART and RS232 both use the same serial bit protocol along with the concept of # of data bits, the use of parity (even/odd/none), and the number of stop bits (1/2). Technically RS232 also implies the electrical definition of using +12V and -12V to denote the marks and spaces (1's and 0's), specific status or control signal pins having a specific meaning such as DTR (data terminal ready), CTS (clear to send), and RTS (request to send). Additionally, RS232 came with the concepts of the type or 'role' of each side in the form of DTE (data terminal equipment) and DCE (data communications equipment). But in the past couple of decades or so the phrase 'RS232' has been abused to simply imply a serial protocol as defined above in the first sentence. If the signals available are only TX, RX, and GND, then usually the terms serial/UART/RS232 are interchangeable. But if there are the additional signals such as CTS, RTS, and/or DTR then this is usually still referred to as RS232. Note that even in these situations the signal levels might still just use 5V and 0V to denote marks and spaces. So that being said, if the equipment being used is ~20 years or older you would do well to use a multimeter to measure the voltage level between the TX line and ground to verify whether it uses simple +5V and 0V to denote marks and spaces as opposed to the older standard definition of RS232 which also implied the positive and negative voltage levels used and limitations on the max capacitance of the cable length. I hope that helps a little, ripred Answer from ripred3 on reddit.com

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r/arduino on Reddit: Is RS-232 UART???

June 27, 2024 -

Is RS-232 UART? I gave a rs-232 port on my laptop (hp probook 6560b) and i want to use it as UART transceiver. In rs-232 there are rx and tx pins (just like uart) so i thought if rs-232 is uart. It can be very useful (like arduino flashing without the pcb)

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The basic answer is yes: UART and RS232 both use the same serial bit protocol along with the concept of # of data bits, the use of parity (even/odd/none), and the number of stop bits (1/2). Technically RS232 also implies the electrical definition of using +12V and -12V to denote the marks and spaces (1's and 0's), specific status or control signal pins having a specific meaning such as DTR (data terminal ready), CTS (clear to send), and RTS (request to send). Additionally, RS232 came with the concepts of the type or 'role' of each side in the form of DTE (data terminal equipment) and DCE (data communications equipment). But in the past couple of decades or so the phrase 'RS232' has been abused to simply imply a serial protocol as defined above in the first sentence. If the signals available are only TX, RX, and GND, then usually the terms serial/UART/RS232 are interchangeable. But if there are the additional signals such as CTS, RTS, and/or DTR then this is usually still referred to as RS232. Note that even in these situations the signal levels might still just use 5V and 0V to denote marks and spaces. So that being said, if the equipment being used is ~20 years or older you would do well to use a multimeter to measure the voltage level between the TX line and ground to verify whether it uses simple +5V and 0V to denote marks and spaces as opposed to the older standard definition of RS232 which also implied the positive and negative voltage levels used and limitations on the max capacitance of the cable length. I hope that helps a little, ripred

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Strictly: RS232 is an electrical standard that defines the voltage levels for serial transmission. A UART is a device that 'talks' serial - UARTs are part of many microcontrollers. But people often use the terms interchangeably, mainly because they use the same protocol so from a software perspective they are the same. One important difference is that RS232 levels are approx +/-12V whereas the UART signals that come out of your chip are 5V/0V or lower - commonly called TTL level AND they are opposite polarity - a 0V UART level is +12V on RS232 so you need a converter chip to translate between true RS232 and TTL level UART signals.

Stack Exchange

electronics.stackexchange.com › questions › 110478 › difference-between-uart-and-rs-232

serial - Difference between UART and RS-232? - Electrical Engineering Stack Exchange

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No, UART and RS-232 are not the same.

UART is responsible for sending and receiving a sequence of bits. At the output of a UART these bits are usually represented by logic level voltages. These bits can become RS-232, RS-422, RS-485, or perhaps some proprietary spec.

RS-232 specifies voltage levels. Notice that some of these voltage levels are negative, and they can also reach ±15V. Larger voltage swing makes RS-232 more resistant to interference (albeit only to some extent).

A microcontroller UART can not generate such voltages levels by itself. This is done with help of an additional component: RS-232 line driver. A classic example of an RS-232 line driver is MAX232. If you go through the datasheet, you'll notice that this IC has a charge pump, which generates ±10V from +5V.

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UART (or USART) - Universal (Synchronous) Asynchronous Receiver/Transmitter

This is, essentially, a serial communications interface. The "universal" part means that it can be configured to support many different specific serial protocols. The term is generic, and does not represent a specific standard. At minimum it means that it has a TX and an RX line, which sends a serial data stream and receives a serial data stream.

RS-232 - A standard defining the signals between two devices, defining the signal names, their purpose, voltage levels, connectors and pinouts.

This is a specific interface standard that allows for equipment interoperability. While two pieces of hardware may have UARTs, you don't know that they'll connect without damage, or communicate properly unless you know they have the same pinout and voltage standards, or include a converter or specially wired cable specific to the interconnection of these two specificl devices. To avoid the need for special converters or cables, the manufacturers may choose to follow the RS-232 standard. You know, then, that a standard RS-232 cable will connect the two.

However, neither the UART, nor the RS-232 standard define what is sent on the TX and RX lines. Generally, when people use RS-232, they use a simple 8 bit NRZ encoding with one start bit and one stop bit. Most equipment today manufactured uses this encoding, but there's no requirement to do so. You can find older equipment that includes parity bits, or uses 7 or 9 bits. The UART can be configured to support these various protocols on its TX and RX lines.

UARTs do not typically interface directly with RS-232. You will need to convert the output of the UART to the +/-12V standard that RS-232 requires. A complete RS-232 interface will typically involve both a UART and an RS-232 level converter. Further, the RS-232 standard includes the definition of several other signalling pins besides TX and RX, which you may need to use depending on the equipment you need to connect to. These will also need to be level converted, and your UART may, or may not, support these signals. If it does not you will have to control them with your software/firmware directly.

So while a UART may help you implement an RS-232 interface, it is not an RS-232 interface itself.

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