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I have a HP50g and TI84 calculator, and was curious about the possibility to link them, writing a program to send numbers/strings/data. Both can be linked via USB, but the TI uses its own special protocol, and the HP uses Xmodem/kermit. The HP manual doesn't seem to show any command to send raw data, if I'm not mistaken, and I don't believe the TI has any command to send bytes across the wire either. Would HPGCC or assembly be the only way to make a program like this?

AstroCB
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NoBugs
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    According to Wikipedia, the TI84 supports USB OTG meaning it could act as a host to the HP50g. I'm guessing the HP50g enumerates as a COM port or a modem (you can check from a host PC). Is there any indication that the enumeration process completes successfully when the calculators are linked? – Stephen Niedzielski Jul 04 '12 at 23:06
  • Interesting wiki article. No wonder the TI calc-calc cable has a "A" on one end, "B" on the other. The A fits in the TI, the B fits in the HP. No, I have no confirmation that they even start to communicate. Is there a baud rate I should set on the HP? – NoBugs Jul 05 '12 at 00:06
  • Baud rate doesn't matter if the device never enumerates. I recommend connecting the HP to a PC and verifying it has enumerated properly (i.e., on Windows use Device Manager). Note the device class. Then look for an icon or app on the HP that indicates it is connected. Once you have a means to determine the enumeration is successful on the calculator itself, you can connect the HP to the TI and check similarly. Look around for a list of supported TI peripherals. Some embedded host controllers only support a few specific devices or device classes. Some even filter by USB vendor and product ID. – Stephen Niedzielski Jul 05 '12 at 02:26
  • You should look at [usb8x](http://usb8x.sourceforge.net/). They've done most of the hard USB stack work for you. Good luck! – George Hilliard May 22 '14 at 13:58
  • It's been awhile since I tried this, but one calculator reset itself because it expected charging voltage through USB I believe. – NoBugs May 23 '14 at 00:49

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