1. Overview. The 232 interface is a common serial communication interface used to connect computers and other devices. The traditional 232 interface requires five wires to be connected, including the transmit line (TXD), the receive line (RXD), the ground wire (GND), and the control line (RTS and CTS). However, in practice, in order to simplify the connection and reduce the cost, sometimes only 3 wires are needed for the connection. The following describes how to connect the 232 interface with only 3 wires.
Second, the connection. 1.Transmit line (txd).
A transmit line is a line that is used to send data. In the 3-wire connection, a separate wire can be used as a transmit line and connected to the output pin of the transmitter chip. It is important to note that the transmit line should have sufficient drive capability to drive the remote receiver chip.
2.Receiver Line (RXD).
A receiver line is a line that is used to receive data. Similarly, in the 3-wire connection, a separate wire can be used as a receiver wire to connect to the input pin of the receiver chip. The drive capability of the receiver line does not need to be very strong, as the receiver chip is usually a high-impedance one.
3.Ground wire (GND).
The ground wire is the line used for signal reflow. In the 3-wire connection, a separate wire can be used as a ground wire to connect to the common ground of the two devices. The role of the ground wire is to provide a reference level to help the signal be transmitted correctly.
Third, the working principle.
In a 3-wire connection, the transmitting chip sends data to the transmit line and returns a signal through the ground wire as a backstream. The receiving chip reads the data from the receiving line and returns a signal through the ground wire as a reflow. Since the ground wires of the two devices are connected, the signals between the transmitting chip and the receiving chip can be transmitted correctly.
It should be noted that since there are only 3 wires to connect, there may be some problems when sending and receiving data. For example, the signal between the transmitting chip and the receiving chip can be interfered with or generate noise. In addition, since there is no control line for flow control and handshake, there may be data loss or transmission errors. Therefore, in practical applications, if it is necessary to ensure reliable data transmission, it is recommended to use the traditional 5-wire connection method or other more reliable communication protocols.
4. Precautions.
1.When using a 3-wire connection, it should be ensured that the drive capacity and impedance matching of the transmit and receive lines meet the requirements of the specification.
2.The ground wire should be connected stably and reliably to avoid signal interference and noise problems.
3.When connecting the equipment, make sure that the connection is correct and avoid short or open circuits.
4.When communicating, it is important to ensure that the data transmission rate and format meet the requirements of the specification to avoid data loss or transmission errors.
5.If you need to ensure reliable data transmission, it is recommended to use the traditional 5-wire connection or other more reliable communication protocols.