TNC31S (TNC31SX) Specifications

Power supply

12 V DC (8...25 Volt) , 60 to approx. 350 mA (depending on modems, supply voltage and software).


ca. B=104, T=130, H=42mm, mass 400 gramm

Modem interface

20-pin connector for flat ribbon cable: GND, 5 Vt (max. 400 mA for both modems), TxD, RxD, TxClock, RxClock, DCD, PTT, CTS, Reset. Baud rate 0 up to 1,2 MBaud, TTL-levels (CMOS). Protocol: AX.25 HDLC (Amateur Packet-Radio Standard)

LED display

PWR, CON (Connect), STA (Status), HALT/ERROR


Motorola MC68302 with 14.7 MHz clock, 8 bit external bus to RAM and ROM, battery buffered CMOS-RAM and (TNC31SX only) real-time clock chip.


75 baud up to 115200 baud, no hardware-handshake, software-selectable

The TNC31 includes...

The TNC31S (TNC31SX) base model consists of the motherboard with 128 kByte (512 kByte) CMOS-RAM and 128 kByte (512 kByte) Flash-EPROM but with NO modems. As modem, you can select one out of a variety of AFSK and FSK modems, which will is built-in according to your order. If you order different modems later, it is easy to change the modem later by the customer.

For operation of TNC31 you need a additional cable between the modem (5 pin DIN connector) and your radio. Power supply and RS232 cable (9 pin sub-d female at the computer side) are included.

Modems and optional memory etc. is ready built in. The TNC31 is supplied with english language manuals (for customers outside of Germany, Austria and Switzerland) and with a 3 1/2 inch software disk.