3 Things You Need to Know About Handshake Lines – RS232

Ready to optimize the value of your RS232 monitoring hardware? You’ll first need to learn about RS232 handshaking – because with the best handshaking hardware, you’ll have no trouble managing the flow of data across equipment using a serial connection.

RS232 handshaking, also known as “flow control,” serves as a viable option for hardware prototyping, software development and production testing. And ultimately, understanding RS232 hardware handshaking is crucial for many hardware and software engineers worldwide.

Here are three things you need to know about RS232 handshaking and its impact on a serial port’s transmission of data.

RS232 Handshaking Lines

RS232 Handshaking Lines

1. A handshaking exchange begins the flow of data on an RS232 link.

Successful transmission of data on an RS232 link requires handshake lines, i.e. control signals that indicate data is ready to be sent and received across equipment.

There are several types of handshake lines, including:

  • RTS – Request to Send
  • CTS – Clear to Send
  • DTR – Data Terminal Ready

Handshake lines also ensure line receivers can decode data without errors. As a result, they enable you to enjoy successful RS232 communications and guarantee data can be exchanged quickly and efficiently.

2. RS232 handshaking involves a step-by-step process.

The RS232 handshake process involves four steps:

1.      The data terminal equipment (DTE) puts the RTS line into the “On” state.

2.      The data communications equipment (DCE) puts the CTS line into the “On” state.

3.      The DTE puts the DTR line into the “On” state.

4.      The DTR line remains in the “On” state while data is being transmitted.

After the transmission of data is completed, the DTE puts the DTR and RTS lines into the “Off” state and the DCE puts the CTS line into the “Off” state.

With RS232 handshaking, RS232 communications only will take place when both ends of the RS232 link are ready. Thus, the RS232 handshake process enables the DTE to request control of the communications link from a related modem and allows the modem to inform the terminal equipment that the control has been acquired.

3. RS232 handshaking serves an important purpose.

There is one important reason why RS232 handshaking can serve you well:

Handshake lines ensure a computer won’t transmit data if the receiving computer is not ready.

It is crucial to note that you can tie handshake lines to fixed voltages. This ensures the handshake lines will remain operational consistently.

Furthermore, RS232 handshaking is not always necessary. And even though your RS232 monitoring hardware may be equipped with inputs and outputs that can be used for handshaking, there is no guarantee that handshaking is needed to optimize the value of your hardware.

Determining whether you need RS232 handshaking may be difficult, but the hardware and software engineers at Stratus Engineering can help you achieve your data transmission goals. We’re an engineering design services firm with application expertise and comprehensive hardware and software engineering experience and will be able to help you master RS232 handshaking in no time at all.

Want to learn more about the ins and outs of RS232 handshaking? Please contact Stratus Engineering today, and we’ll be able to help you maximize the value of your RS232 monitoring hardware.