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RS232 Evaluation Kit

Hi, guys I'm exploring some Integrated Circuit to use it in an RS232 application, so I found that there exists this Evaluation Kit  DC827A-B, and I'd like to understand the connections in the schematic.

Specifically, in pg 4 there it is showed the schematic, and J1 represents the DB9 connector for stablish an RS232 communication. My doubt is: pin 2,  RD (RX pin as per the standard) is connected to T1out, but this T1out  is an output from the IC LTC2804, and there it is my confussion. So, if a pin is for RX operation, I understand it is used to receive data (so in one device I transmit with TX and at the other device I receive with RX), so in this case RD should be connected to a receiver pin, e.g, RXIN. What am I missing here?


Fig.1. Connector

  • Thanks for your query, 

    This is due to a naming convention depending on whether the equipment is on the device side (DCE) or PC side (DTE).

    For DCE equipment (Device side), pin 2 is typically TxD and pin 3 is typically RxD.
    This is how the LTC2803 on the DC827A-B board is connected to the DB-9 connector.

    For DTE equipment (PC side), Pin 2 is typically RxD and pin 3 is typically TxD. The terminal of the J1 connector on Page 4 are lablled according to the DTE convention.

    When connected to a PC, Pin 2 (Tx) of the DC827 will be connected to Pin 2 of the PC port (Rx), and Pin 3 (Rx) of the DC827 will be connected to Pin 3 of the PC port (Tx)

    The same convention is true for the RTS and CTS connections on the DB-9 connector. DCE equipment has pin 7 has CTS and pin 8 as RTS. DTE equipment has pin 7 as RTS and pin 8 as CTS.



  • Thank you for your answer and for your time, Neil.