TNCPi TNCX for Raspberry Pi Have Your Pi a la mode! There is now a new version of the TNCPi designed to fit the Raspberry Pi model B+ and Pi 2 perfectly! See below for details! 
The original TNCPi sits atop Raspberry Pi version B. The 9 pin Dsub connector interfaces to your radio. 
TNCPi is a special version of TNCX designed to interface directly with the Raspberry Pi computer. It can connect to the Pi either via the Pi's serial port, or via the I2C protocol. In the latter case, a single Pi can support multiple TNCPi's at the same time, since each TNCPi can be given a unique I2C address. The firmware for TNCPi was based on the original TNCX open source code by John Hansen, W2FS as modified by John Wiseman, G8BPQ to support the I2C protocol as well as the original serial port connection. 
Here is the new Pi 2 sitting atop a Raspberry Pi version B+. It also fits the Pi 2 perfectly. 
The TNCPi 2 is Now Here! The TNCPi 2 is designed to perfectly match the form factor of the new Raspberry Pi B+ and Raspberry Pi 2 models. All 40 header pins are communicated to the top of the TNCPi 2 board. The standoff has been repositioned to the bottom left corner to add greater stability. The TNCPi 2 no longer needs any jumpers to be configured. Otherwise the TNCPi 2 is functionally identical to the original TNCPi and there have been no changes in the firmware. The new TNCPi 2 is designed to fit the B+ and Pi 2 boards only. The original TNCPi will also fit the B+ and Pi 2 board, but because it was designed for the original Pi version B, the form factor is not the same and only the first 26 pins are communicated through the TNCPi board. The original TNCPi will continue to be available indefinitely. 
There are lots of potential applications for TNCPi. Here you see the APRS program Xastir running on the Pi driving a TNCPi via the serial connection. With this setup you've got most of the functionality of a D700/Avmap combination at less than a quarter the cost. A Linux version of the WinLink program Paclink is currently under development. Imagine how small your WinLink station can be if you build it around a Raspberry Pi/TNCPi combination? 

Imagine running a pair of TNCPi's with a single Raspberry Pi to create a dual frequency digipeater. G8BPQ has created a new version of his venerable BPQ multiport packet program that will support this.  
Here's a Raspberry Pi with a TNCPi stacked on top of it. On top of that is a $35 Adafruit PiTFT Display. It's a 2.8 inch touchscreen display. It's running Xastir. 
TNCPi is a fun, easy to build kit. All parts are throughhole; there's absolutely no surface mount soldering involved. You can view a copy of the manual here. It is shipping now and is $10 cheaper than the original TNCX! If you have any questions contact John Hansen W2FS at: john@coastalchip.com. 