Your correct, USB does stand for Universal Serial Bus, but it is just an unfortunate similarity in naming.
The (simplified) definition of Serial, is to send 1 bit after the next. Since the USB interface works in that manner, they felt it acceptable to name it Universal Serial Bus. The hard drive in a modern computer also works on a similar principal, and thus it is called Serial ATA. Unfortunately serial, as defined conventionally in desktop computers and radios, refers to (most commonly) the RS-232 specification. In our radio-centric world it can also commonly mean TTL, which is easily convertible by changing the levels. For GPS it implies RS-232. When the USB specification was in process, they thought of all the common uses for it and created what are referred to "Class Drivers" for each device. Cameras, Keyboards, Mice, hard drives, etc. That is why you don't need a driver when you plug your USB keyboard in to make it work and why your thumbdrive just works when you plug it in. They were designed to conform to the class driver for their respective device type and all modern operating systems include a complete set of Class Drivers. Now, when they were doing this, they forgot to create such a driver for a serial port. This has caused a number of issues for hams over the last few years as we slowly transition, and is primarily responsible for why some USB->Serial adapters work very well and some don't work well at all. Our devices generally demand very strict compliance and not all USB->Serial drivers are created equally. As hams, it would have simplified our lives greatly had they included a USB class driver for all Serial Devices. All of our USB->Serial adapters would work properly, the gentleman who recently posted about his OPC478UC nightmare would not have had a problem. I know I left topic a bit, I apologize. I hope I answered your question. In a nutshell, yes, USB is still a serial interface, but it is not THE serial interface that we are used to dealing with as hams. Barry A. Wilson wrote: > > > Mike, > > This may be a bit of semantics but for the sake of argument if the USB > interface on the Garmin GPS isn't serial. then what is it? >
