The RS 232 interface is one of the standards used in serial communications. It uses serial signals (as opposed to parallel) to connect computers to devices like printers and modems.
RS-232
The 232 doesn't stand or come from anywhere. It's just a reference number. RS-232 = Recommended Standard 232
Whwn an IC is connected to a PC, then the voltage levels of these two should be synchronized. For this purpose, the TTL voltage level is converted to RS 232 level. RS 232 is the interface between a PC and an IC.
The GPS system provides location information that can be fed into the RS 232 tester via a compatible interface. The RS 232 tester then receives and processes this location data to perform testing or analysis on devices or systems that rely on accurate geographical positioning. This integration allows for precise testing and verification of location-based functionalities.
Recommended Standard 232
It refers to the 25-pin or 9-pin male serial port on the back of a PC. "A serial port conforms to the interface standard called RS-232c (Reference Standard 232 revision c), which is why a serial port is sometimes called the RS-232 port. The maximum cable length for a serial cable according to RS-232 standards is 50 feet. This interface standard originally called for 25 pins, but because microcomputers use only nine of those pins, manufacturers often installed a modified 9-pin port." -CompTIA A+ Guide to Managing & Maintaining You PC Sixth Edition
onion
Originally - that was the RS-232 interface. That has since been superseded by the USB format.
Serial interface transmits one bit at a time, typically using a single data line. Examples include USB, RS-232, and SPI interfaces.
You can do it directly from a serial port of the PC to the CPU's Modbus port (if you are using a Modicon controller). The standard used would be RS-232.
The ELM327 has a low function.It has a simple interface which is called via UART. It monitors like a diagnostic tool connected by Bluetooth,RS-232 or a USB.
Its a 8051 based CPU with inbuilt flash memory(ISP - In-System Programming). It can be flashed through SPI(serial peripheral Interface). AT89C51RD2 has similar features but its flash memory can be programmed through serial interface (RS-232).