Thread: RS232 Pin Out question

  1. #1
    Registered User
    Join Date
    May 2004

    RS232 Pin Out question

    following a link from another post I have been researching some RS232 basics and my question is:

    In general the articles I have read state that pin 2 - on the female side - going to the pc is the Recieve data pin, so it should receive byte data coming in, correct?

    Pin 5 is designated as the signal ground in the PC side of the cable?

    So if I have my documentation correct on the device that is broadcasting the signal and it states that pin 8 is the transmitting data out from device pin and pin 2 is the power and signal ground pin

    should my pin to pin mapping not look like this:

    PC Device
    REC pin 2 <- Trans pin 8
    Grd pin 5 <-> Grd pin 2

    I ask, because thats what I built and I am getting nothing. I have a known good program that receives serial input from the port on the same pc, from a basic stamp devices that uses standardized pin out protocols. There are other pins in the device documentation that state for data into device or power transmitted from the device, but I did not include those pins in my cable because I did not think they would be necessary, which could be causing my problem if I am wrong.

    Device Pin Out:
    1 +12volts from power supply
    2 Poewr and signal ground
    3 +8 volts from counting unit
    4 Data in from optional hand cord
    5 (not used)
    6 (not used)
    7 RS232 Data in (to counting unit)
    8 RS232 Data out(from counting unit)
    9 (not used)

    As always any help or ideas are greatly appreciated.

  2. #2
    Just Lurking Dave_Sinkula's Avatar
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    Oct 2002
    7. It is easier to write an incorrect program than understand a correct one.
    40. There are two ways to write error-free programs; only the third one works.*

  3. #3
    Registered User
    Join Date
    May 2004
    yep, thats the link I got from the other post, should have put that in there, but eitherway I found my issue, I had the pinout correct, it was port polling issue that was the problem, and a another output setting on the device.


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