TNC-X - The Expandable TNC

The First TNC to Offer Both USB and Bluetooth

Just $50!

BlueTooth is Now Available for TNC-X!

--So you can now use APRS from your Android SmartPhone (details here)!

goto ordering information

goto USB driver installation information

TNC-X Documentation Page (manual, schematic, source code, etc.)

Setting Up TNC-X to work with AGWPE

What is a "KISS Mode" TNC and why would I want one?


Here's how to build a TNC-X in 4 minutes (Special Thanks to Jack Weill, KF7VFX):


NEW!!! TNC-Pi    A Specialized version of TNC-X For the Raspberry Pi

TNC-Pi is a special version of TNC-X 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 TNC-Pi's at the same time, since each TNC-Pi can be given a unique I2C address.

X-BT is Now Available

Aprs on Your Android Smart Phone

X-Digi is Now Available!

An Inexpensive Digipeater Daughterboard for TNC-X!

X-Track is Now Available

An Inexpensive Tracker Daughterboard for TNC-X!

TNC-X with USB option installed

TNC-X is a new Terminal Node Controller (kit) design based on the Chepponis/Karn KISS protocol. It is implemented using a Microchip PIC 16F628A microcontroller, a CML MX614 Bell 202 modem chip, an 8K Ramtron FRAM, a MAX232A level converter chip, and an op-amp which provides active audio filtering for the modem. From the beginning, this TNC was designed to be small, inexpensive, have low power consumption, and expandable. TNC-X features an 8 pin expansion header that allows the addition of "daughter boards". Power is provided to the daughter board through the expansion header. In addition, signals that would otherwise go to or from a host PC can be intercepted by the daughter board at the TTL level and processed. The I/O on the expansion header speaks "KISS" so that any daughter board only has to send and receive data packaged in KISS format to access the core module. This makes the development of daughter boards fairly simple and inexpensive. For example, daughterboards are now available that can turn TNC-X into either of two types of digitpeters (see uSmartDigi and X-Digi) or into a stand alone Tracker (see X-Track). In addition, the expansion header provides access to a second on-board serial port. The X-Track daughterboard, for example, uses this port to receive data from a GPS receiver. The data is then processed and formed into packets and an APRS beacon is sent.

TNC-X is available in two versions: with and without a USB port. Both versions contain a standard serial port, but the USB version also allows the TNC to be connected to a computer via it's USB port as well. Drivers that are shipped with the module make it appear to the host PC as a standard serial port. Thus PC software that expects to see a serial port on the computer will interpret the TNC-X as being connected to such a port, even when the PC has no serial ports, or they are all used by other applications. In addition, when the USB option is used, the TNC can be powered from the USB port of the computer; no other power supply is needed.

Even without daughter boards (or the USB option) the device works as a fully functional stand alone KISS mode TNC. The idea behind the expansion options was to provide a platform that would allow additional functionality to be added to the unit with the investment of very little design time and very few parts.

A complete technical description of TNC-X is provided in a paper that was presented at the 2003 ARRL/TAPR Digital Communications Conference in late September in Hartford Connecticut. A copy of this paper can be accessed here. Please note that there have been a few design changes since the publication of this paper. At some point I will revise the paper, but I've not as yet had an opportunity to do so.

Any questions concerning TNC-X can be directed to the developer, John Hansen, W2FS.

TNC-X rev 2.6 Kit without enclosure or USB($50 plus shipping)

Wiring, Assembly and Testing Service - Complete Unit ($35)

USB option for TNC-X ($20)

Note: This option works only with rev 2.6 boards and must be ordered at the same time as TNC-X.

BlueTooth Daughter Board Option for TNC-X ($25)

TNC-X Custom Drilled Enclosure for TNC-X ($18)

Note: This enclosure will only work with revision 2.2 thru 2.6 boards.

5 Pin DIN Plug to mate with the DIN radio connector on the back of TNC-X. ($2)

Note: The radio connector on the back of TNC-X is designed to work with pre-wired MFJ and BuxComm TNC to Radio cables. Or you can build one of your own. This plug, which used to be available at every Radio Shack store, is no longer carried there. For your convenience, you can order one here if you need it.

Here are some common configurations you can order with one button press:

Complete TNC-X kit with USB and Enclosure ($88)

Complete Wired and Tested TNC-X including USB and Enclosure ($123)