Supports only point-to-point communication, that is, one 232 interface can connect to only one 232 device.
Using serial extension chip, WK2204 or WK2168, via SPI/I2C/UART/8Letters, connections, etc.
Communication Different RS-232 only allows one-to-one communication, while the RS-485 interface is allowed to connect up to 128 transceivers on the bus. RS-232 is defined as a single-ended standard that increases the communication distance in low-rate serial communications. Different wiring RS232 is three-wire system, RS485 is two-wire system.
Difference between RS232 and RS485 RS232 uses three-core communication, RS485 uses two-core communication, both of them can use DB9 interface. In specific use, RS232 The transmission distance is relatively short, and the RS485 transmission distance is relatively long.
It is very common to convert TTL serial signal to RS232 serial signal level conversion chip. This chip price is much lower than max3232 price, reliable performance, is a good alternative. The amount is enormous.
A notebook with a serial port is one of the computersA 9-pin jack, now most computers do not have this jack, can be replaced by USB to serial port software and cable.
The only difference between RS232 and TTL is the hardware: the logical meaning of the level representation is different (in reverse).