What is the Difference Between RS232 and RS485?

RS232 and RS485 are both serial communication standards, but they have some key differences:

1. Data Transfer Speed: RS232 supports data rates up to 3 Mbps, while RS485 can achieve data rates up to 40 Mbps.
2. Maximum Distance: RS485 cables can extend data up to 4,000 feet, whereas RS232 cables can only transmit data up to 50 feet.
3. Electrical Specifications: RS232 uses single-ended signaling, which means one wire transmits data and another wire receives data. RS485, on the other hand, uses differential signaling, employing two wires to transmit data. This makes RS485 more resistant to noise and interference.
4. Number of Devices: RS232 is designed for connecting two devices, with one transmitter and one receiver. In contrast, RS485 supports multipoint configurations, allowing for the connection of up to 32 devices on the same bus.
5. Voltage: RS232 uses a voltage range between +12V to -12V, while RS485 uses a voltage range between +5V and -5V.
6. Wiring: RS232 cables typically have up to 25 wires, while RS485 cables have only 3 wires (one for ground and two for sending data).

In summary, RS232 is more suitable for short distances and slow data rates, while RS485 is better for longer distances, higher data rates, and configurations with multiple devices. RS485 is more resistant to noise and interference due to its differential signaling method.

Comparative Table: RS232 vs RS485

Here is a table summarizing the main differences between RS232 and RS485:

RS232 is a full-duplex communication protocol, while RS485 is a half-duplex protocol. RS485 can provide a longer operational distance and higher noise immunity compared to RS232. Additionally, RS485 supports more transmitters and receivers than RS232. Both standards are widely used in various applications, such as scientific equipment, industrial wireless controls, computers, robots, and medical equipment.