Hi Kelvin, I understand that you want to control pins on your serial port using LabVIEW. Since you are using Windows XP, only LabVIEW version 7.0 will be able to control the pins. The pins can be controlled by modifying the values of the access registers that windows associates with each pin. If you are using LabVIEW 7.0, then the VI's located on the Funtions >> Advanced >> Port I/O palette should help you assign values to the proper pins. This information can also be found on another discussion forum thread located at the following url: http://exchange.ni.com/servlet/ProcessRequest?RHIVEID=101&RPAGEID=135&HOID=506500000008000000438A0000&UCATEGORY_0=_49_%24_6_&UCATEGORY_S=0
Thanks for contacting NI, and I hope this helps. Marcus G. National Instruments