This cable connects to an external device, such as a PC or PLC, and enables the recording of results and changes in measured values via RS-232C communication.
An RS‑232C cable is a serial communication cable used to connect Data Terminal Equipment (DTE), such as computers, to Data Communication Equipment (DCE) like modems or instruments. It follows the RS‑232C (or EIA‑232‑C) standard for voltage levels, pin configurations, and connectors.
The most common connectors are DB‑9 (DE‑9) and DB‑25 D‑sub connectors. DB‑9 is widely used today due to its compact size, while DB‑25 was more prevalent in early implementations.
Despite the rise of USB, RS‑232C remains common in industries for connecting lab test equipment, sensors, industrial controllers, and instruments. It’s valued for its simplicity and robustness.
A straight-through cable connects matching pins (e.g., pin 2 to pin 2) and is used when connecting DTE to DCE devices.
A null‑modem cable crosses transmit and receive pins to allow direct connection between two DTE devices (like two PCs).