What is RS232?
When working with Serial Communication, you’ll bound to come across the term RS-232. What’s RS232 you may ask?
RS232 is the first serial communication protocol that’s widely used as a communication method for computers and devices by serial ports. Similar to your microcontroller serial signals, it transmits data a bit at one time.
RS232 works by connecting Data Transmission Equipment (DTE) and Data Communication Equipment (DCE), which has pins like TXD, RXD, and RTS&CTS.
- TXD: Transmitter
- RXD: Receiver
- RTS: Request to Send
- CTS: Clear to Send
- GND: Ground
RS232 Features and Parameters:
| Parameters | RS232 |
|---|---|
| Transmission Mode | Simplex |
| Max connected devices | 2 devices: 1 driver, 1 receiver |
| Max. transmission rate | 20Kbps |
| Max. cable length | 15m |
| Operation mode | Single-ended (unbalanced type) |
| Features | Short distance Full-duplex 1:1 connection |
Advantages and Disadvantages of RS232
Advantages
- Low cost
- Widely available and applicable due to its long presence in the telecommunications industry
- Simple wiring and connectors with only max support for 1 driver and 1 receiver
Disadvantages
- Data transfer speed floats around 20kilobytes per second, slower than what we’re used to now
- No more than 50 feet apart for a point-to-point connection between a computer and device
What is TTL serial?
TTL stands for Transistor-Transistor Logic, a serial communication commonly found in UART (universally asynchronous receiver/transmitter) transmission method, a method seen in most microcontrollers these days.
Advantages and Disadvantages of TTL Serial
Advantages:
- Low cost
- High availability
- High compatibility with microcontroller
- Ease of usage
Disadvantages:
- Noisy, due to poor noise margin
- Limited speed and frequency
- Higher power consumption at higher frequencies
The two protocols differ in the following ways:
