4) WHAT ARE DATA LINES ON AN RS232 DEVICE?
Answer: Data Lines are the signal lines are used to transmit and receive data bi-directionally between a DTE and a DCE. The two data lines are the TX (transmit) and RX (receive). An RS232 port is full duplex, meaning the port can both transmit and receive data simultaneously. DB25 equipped DTEs transmit on pin 2 and receive on pin 3; and 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, and DB9 equipped DCEs transmit on pin 2 and receive on pin 3. When cabling, check that the transmit and receive signal lines are on the proper pins.