The TI nspire calculator is an advanced calculator which is expected to be the successor of TI-89. There are news on the web that a recent OS update (version 4.2) to the TI Nspire calculator added serial interface support to its programming environment.
Before this OS release, the USB port is intended only for PC data connectivity (PC software for this calc is free with every purchase of the calc, and runs exactly the same as the real calculator on PC) and charging of calculator battery.
Although this feature is not highlighted in the release notes, some calculator enthusiasts reported