Confused on protocol and interface

Thread Starter

skyr6546

Joined Mar 22, 2019
55
I am confused by these three issues: interface, standard and protocol, I am trying to understand their difference and want to discuss them here.

Based on my understanding, interface determines hardware , like sensor, LCD . On the contrast, protocol defines programming Uart, I2C,SPI, Rs232

I don't know whether my understand is right. Hope anyone who is familiar with this can help me understand.
 

atferrari

Joined Jan 6, 2004
3,484
Have you even tried to look in the Web? Thousands of definitions relate those expressions.
Such a generic request is better served in the Web.
In forums like AAC is better to look for doubts on details.
 

MrChips

Joined Oct 2, 2009
19,378
Depends. They could mean the same thing. Or they could mean different things.

An interface is a go-between. Something or someone that bridges a gap or connects between two parties. It could also mean collaboration between two parties or two devices.

A standard is a method/procedure/specification that has acceptance among many users.

A protocol is the method/procedure/specification used in the design and operation of whatever. It does not require universal or mutual acceptance. You can create your own protocol and have no one else adopt it.
 

Thread Starter

skyr6546

Joined Mar 22, 2019
55
Have you even tried to look in the Web? Thousands of definitions relate those expressions.
Such a generic request is better served in the Web.
In forums like AAC is better to look for doubts on details.
I looked at google see result https://www.google.com/search?rlz=1C1CHBF_enIN855IN855&biw=1366&bih=608&sxsrf=ACYBGNTxh1NVYLktahWT8JQqzGGvbWDBgw:1572375575367&ei=F4y4XYqHFqWdmgeLuLLQCA&q=rs232+interface+or+protocol&oq=rs232+interface+or+protocol&gs_l=psy-ab.3..0i22i30.32109.48402..50186...0.2..1.567.7898.0j14j16j2j0j2......0....1..gws-wiz.......0i71j35i304i39j0i8i7i30j0i8i30j33i22i29i30.sR2grKHMnEQ&ved=0ahUKEwjK7v28k8LlAhWljuYKHQucDIoQ4dUDCAs&uact=5

Look at 4th link wiki page It say Rs232 is interface while other says its protocol
 

SteveSh

Joined Nov 5, 2019
90
I don't the RS-432 standard defines the protocol. It defines the signal type, voltage levels, and pin outs for connectors. It reside at layer 1, the physical layer, of the OSI model.
 

SteveSh

Joined Nov 5, 2019
90
In my earlier post, I meant to say RS-232, not 432. But in any case, neither the ‘232, ‘422, nor the ‘485 standards define a protocol.
 

MaxHeadRoom

Joined Jul 18, 2013
19,156
For the RS232 specification, There is basically a DTE (Data Terminal Equipment) and DCE (Data Communications Equipment) refer to the types of equipment on either end of a serial connection.
The hardware protocol is and has always been In general standard, With the option of using hardware handshake if needed, there are also recognized ASCII codes for software handshake also..
RS232 Serial data is passed from one device to another in ASCII or 8 bit format, It’s up to you to decide how each device (computer or micro-controller) should interpret this Data, when the beginning of a message is, when the end is, and what to do with the Data in between.
Max.
 

SteveSh

Joined Nov 5, 2019
90
There are also recognized ASCII codes for software handshake also..
RS232 Serial data is passed from one device to another in ASCII or 8 bit format, It’s up to you to decide how each device (computer or micro-controller) should interpret this Data, when the beginning of a message is, when the end is, and what to do with the Data in between.
Max.
But, none of this is part of the RS-232 standard. The following is from Wikipedia, and is consistent with my understanding of what defines RS-232:

Scope of the standard
The Electronic Industries Association (EIA) standard RS-232-C[3] as of 1969 defines:
  • - Electrical signal characteristics such as voltage levels, signaling rate, timing, and slew-rate of signals, voltage withstand level, - - short-circuit behavior, and maximum load capacitance.
    • - Interface mechanical characteristics, pluggable connectors and pin identification.
    • - Functions of each circuit in the interface connector.
    • - Standard subsets of interface circuits for selected telecom applications.
The standard does not define such elements as the character encoding (i.e. ASCII, EBCDIC, or others), the framing of characters (start or stop bits, etc.), transmission order of bits, or error detection protocols. The character format and transmission bit rate are set by the serial port hardware, typically a UART, which may also contain circuits to convert the internal logic levels to RS-232 compatible signal levels. The standard does not define bit rates for transmission, except that it says it is intended for bit rates lower than 20,000 bits per second.
 

BobaMosfet

Joined Jul 1, 2009
826
I am confused by these three issues: interface, standard and protocol, I am trying to understand their difference and want to discuss them here.

Based on my understanding, interface determines hardware , like sensor, LCD . On the contrast, protocol defines programming Uart, I2C,SPI, Rs232

I don't know whether my understand is right. Hope anyone who is familiar with this can help me understand.
An interface is a point between two devices (or people) where data is exchanged. For people, it's our mouths and ears.
A standard is a document that outlines the method by which the data is exchanged, so that everyone can do it the same way (with people, it is the grammar that describes your native tongue).
A protocol is the implementation of that standard in logic, so the devices can communicate. In People, it's speaking based on the rules or implied rules of the grammar of your language, and hearing those sounds and understanding their meaning.

Now, if you want to get technical, go to the Telecom Dictionary. It's the defacto standard for all such definitions.
 
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