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GlobalSat BU-355 COM port problem

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  • GlobalSat BU-355 COM port problem

    Hi guys. Ive just bought the above and i cant seem to get it to work. I have a VIA EPIA ML6000EA with a serial port (rs-232, 9 pin d-sub, male). The GPS unit i have bought has a female ps/2 port. Ive connected these using a ps/2 to rs-232. It doesnt work at all, no led's light, it doesnt show on my com port in device manager and the program supplied on cd scans the COM ports and finds "NO DEVICE".

    What am i doing wrong?

    Will i have to buy a ps/2 to usb converter? as the cd has the usb drivers


  • #2


    • #3
      The reason no LEDs lit up is because, when using a serial port for your GPS receiver, there is usually a cable that splits to a ps/2 and a serial port. The receiver connects to the PC through the serial port and receives power through the ps/2 port.

      Thus, your PC is not recognizing the receiver because it has no power. You'll need either what I mentioned above or, like you said, a ps/2 to usb converter since it can connect and draw power through the usb port.

      Strange that your receiver didn't come with the proper connector, though...


      • #4
        well, after spending an hour with a soldering iron and a multimeter i failed to get it to work.

        i was following this diagram:

        Ive connected everything correctly i think. its just i dont know what to do on the rs232 end of the cable. does the serial port only need information from two pins (2 and 3)? what is the need in the rest of the pins? e.g. 1,4,5,6,7,8,9


        • #5
          Make sure all the cables are connected to the corresponding port on either end using the following links as guides to the pinout diagrams.

          PS/2 -> Serial (9 pin)



          • #6

            from there ive connected pins 2 and 3 to the correct pins on the gps mouse, 4 and 5. Ive then connected pins 1 and 2 of the min-din end to +5v and ground. What else do i need to do?


            • #7
              The serial port needs a connection to ground at pin 5.

              Also, check out the last link, the last row in the table on the page.


              • #8
                Would anyone be kind enough to tell me what pins of the rs232 goto which pins of the ps/2 port


                1 CD
                2 RXD
                3 TXD
                4 DTR
                5 GND
                6 DSR
                7 RTS
                8 CTS
                9 RI


                1 = +5V (from floppy)
                2 = GROUND
                3 = ?????
                4 = RECEIVE (PIN 2 of rs232)
                5 = TRANSMIT (PIN 3 of rs232)
                6 = ?????

                What do i do?!

                thanks guys


                • #9


                  • #10
                    bump again. My entire project is on the hold until this is sorted


                    • #11
                      One more bump! someone must have a slight idea!


                      • #12
                        Ok, ive applied +5V and GND directly to the connectors inside the unit. Red (+5V) and Black (GND), the power LED doesnt light up, does that mean i have a broken unit? Could anyone check if the power LED comes on with just the power wires connected


                        • #13
                          Hey Rich,

                          Just random spouting here - I don't have the same unit as yours.... have you checked the continuity between pin 1 on the connector and the red wire on the board and the same with pin 2 to black?

                          Have you done anything bad in your messing about trying to get it to work that might have shorted something? Are there any glass fuses or anything on the board inside that have popped?

                          LED status could be a tricky one..... different receivers do different things, some will flash when powered and then go steady when get a lock, not sure what the standard procedure is for your unit.


                          • #14
                            im not perfectly sure what is meant by continuity but im going to guess! I have a setting on my multimeter that makes a sound when the circuit is completed. If i put one prong on the red and one prong on the black it doesnt make a sound!


                            • #15
                              lol, yeah, that's what I'm talking about, but I mean put one on red and one on pin 1 of your cable to check that the wiring is the same as the diagram to make sure you've not shorted anything when messing about with the serial port and the ps2 connector.

                              Red to black beeping would be a short which is bad