Texas Instruments' Silverlink is a product to connect calculators without USB ports (namely everything except the TI-84 Plus series and the TI-89 Titanium) to computers' USB ports to transfer files, screenshots, and operating systems. The Silverlink was first introduced about fifteen years ago, and the early models are already starting to show their age. A number of Silverlinks, including my own, have failed over time, and we anticipate that the rest will gradually lose their firmwares (with no way of repairing them) in the next decade or two. To fill this gap, ideas for a community-coded Silverlink clone have been kicking around for several years. Tim "geekboy1011" Keller has taken the initiative in creating Silverlink clone software for the Arduino Leonardo (ATmega32U4) microcontroller development board.
Tim started from my Arduino to TI calculator linking routines, which he ported from Arduino "C" to bare-AVR C. He was able to deduce the file transfer protocols from a combination of USB sniffing, the venerable TI Link Protocol & File Format Guide, and occasional sanity-checking against the TILP repository. Tim is using the LUFA library for AVRs to handle USB; the flexibility of the library lets his Silverlink clone appear to be an original Silverlink to the host computer, and thus requires no new drivers. Since it appears to be a regular Silverlink to computer-side software, Tim's clone works with both TI-Connect and TiLP, the two popular software options for linking TI calculators and computers.
We look forward to Tim's continuing work on this project, and hope this and other projects will help retired calculators to remain useable and useful for many years to come. You can find more information about this project as well as an ongoing project log in the topic linked below.
More Information Silverlink clone information and progress log: Cemetech, Omnimaga.