Curious if anyone knows for ocean container tracking, obviously they use a GPS module to get the location, but for transmitting data back to the "home" monitoring station, I would assume that a single satellite transmitter collects data via wifi or some other network from each GPS unit? I can't imagine any other way of it working. Anyone have knowledge on this? -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist