SandeepC

Thanks for the reply Rolf. The reason I am not preferring to connect the device to the USB port of the system is the speed/latency constraint. I need very high speed and low latency and I thought that using the D-SUB port would provide this. One other idea that I have thought about is the use of a USB to Serial port converter. If I connect the USB port of the device to a USB to Serial port converter cable and connect the data pins of the serial output to the TTL pins of the D-SUB. Would this be possible? (In this option also I am alright with the idea of doing away with sending triggering signals to the GPS which can be operated in auto output mode.) Please let me know your thoughts regarding this. Regards, Sandeep

Hi, I need to connect an external device (GPS) which has a USB port to the D-SUB 15 pin port of the PCI 1426 frame grabber. I know that the USB port has a power and ground pins and two data pins. I also know that USB sends out data in differential voltage. But I am not sure whether the frame grabber can detect differential voltage. My requirement is to send triggering pulses to the GPS device and read the responses given by the GPS device. I am thinking of using the TTL I/O 1-4 pins of the 1426 for this. Can any one tell me how this interfacing can be done? Thanks & Regards, Sandeep