Frequently Asked Questions
RS232/RS485/RS422 QUESTIONS
2) WHAT IS AN RS232 DTE AND DCE?
Answer: DTE and DCE are the names assigned to devices which interconnect and communicate over RS232 interfaces. DTE stands for Data Terminal Equipment; a DTE RS232 port typically uses male DB9 or DB25 connector. An example of a DTE is a computer. DCE stands for Data Circuit-termination Equipment; a DCE RS232 port is typically equipped with a female DB9 or DB25 connector. An example of a DCE is a printer or modem. Since the terms DTE and DCE are not particularly descriptive of what they represent, they are often confused. In addition, note that DB25 equipped DTEs transmit on pin 2 and receive on pin 3, whereas DB9 equipped DTEs transmit on pin 3 and receive on pin 2. Conversely, DB25 equipped DCEs transmit on pin 3 and receive on pin 2, whereas DB9 equipped DCEs transmit on pin 2 and receive on pin 3. All this brings to mind a famous quote by Henry David Thoreau: “…consistency is the hobgoblin of feeble minds.“
