Interface : RS232 ,RS 485 and TTL

In the Internet of Things industry, as long as you are an embedded engineer, you will generally be exposed to RS232, RS485, TTL these concepts.

Are you encountered this concept on Baidu search it, below for you to organize the RS232 and RS485, TTL interface differences.
Electrical characteristics of the RS232 interface The voltage of any signal line in RS-232-C is a negative logic relationship.

That is, the logical “1″ is -3 to -15V, and the logical “0″ is from 3 to 15V. RS-232-C connectors are generally modeled DB-9 plug holders, usually plugs at the DCE end and sockets at the DTE end. The RS-232 port of the PC is a 9-core needle socket. Some devices are connected to the RS-232 interface to the PC because only three interface lines are required, namely “send data TXD”, “receiving data RXD” and “signal-to-ground GND” without using the transmission control signal of the other party.

The RS-232 transmission cable uses a shielded twisted pair.
Electrical characteristics of the RS485 (now more commonly used interfaces) RS485 uses differential signal negative logic, the logic of “1″ is represented by the voltage difference between the two lines as -(2 to 6) V, and the logic “0″ is represented by the voltage difference between the two lines as plus (2 to 6) V. The interface signal level is lower than THE RS-232-C, it is not easy to damage the interface circuit chip, and this level is compatible with the TTL level, can be easily connected to the TTL circuit.

The RS-485 has a maximum data transfer rate of 10Mbps.
TTL level TTL level signals are most used because the usual data representations are binary, with 5V equivalent to logic “1″ and 0V equivalent to logic “0″, which is known as ttl (transistor-transistor logic level Transistor-Transistor Logic) signal system.

This is the standard technology for communication between parts of the device controlled by the computer processor.

The difference between RS232 and RS485, TTL

1, RS232, RS485, TTL refers to the level standard (electrical signal)

2, TTL level standard is low level 0, high level is 1 (ground, standard digital circuit logic).

3, RS232 level standard is a positive level of 0, negative level of 1 (to the ground, positive and negative 6-15V can be, and even with a high resistance state). 4, RS485 and RS232 are similar, but the use of differential signal logic, more suitable for long-distance, high-speed transmission.

Post time: Jul-24-2019
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