RS-232 Serial / Modbus Module,DB9 cable

The RS-232 standard was first introduced in 1962 by the Radio Sector of the EIA. The original DTEs (data terminal equipment) were electromechanical teletypewriters, and the original DCEs (data circuit-terminating equipment) were usually modems. For many years, an RS-232-compatible port was a standard feature for serial communications, such as modem connections, on many computers. The RS-232 standard is still used to connect industrial equipment (such as PLCs), console ports and special purpose equipment.

The IEEE RS-232 standard defines electrical, signal timing, and size connectors. Use of a common ground, limits RS-232 to applications with relatively short cables. RS-232 connection consisting only of transmit data, receive data, and ground. RS-232 protocol uses bipolar signal. Valid signals are ±3 to +15 volts, the ±3V range is not a valid RS-232 level. Data signals between -3V and -15V represents a logic 1. The logic 0 is represented by a voltage of between +3V and +15V.

Applications:

• - Dial-up modems
• - GPS receivers (typically NMEA 0183 at 4,800 bit/s)
• - Bar code scanners and other point of sale devices
• - LED and LCD text displays
• - Satellite phones, low-speed satellite modems and other satellite based transceiver devices
• - Flat-screen (LCD and plasma) monitors to control screen functions by external computer, other AV components or remotes
• - Test and measuring equipment such as digital multimeters and weighing systems
• - Updating firmware on various consumer devices
• - Some CNC controllers
• - Uninterruptible power supply
• - Stenography or Stenotype machines
• - Software debuggers that run on a 2^nd computer
• - Industrial field buses

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