The documents, which can be downloaded here are under
Copyright of SYMEK!
It is not allowed to publish these documents or parts thereof without mentioning the source and author.
manual TNC2H, DIN-A-4 Winword. (480kB zip)
manual TNC3S rev. 'K' (Hardware), DIN-A-4 Winword. (850kB zip)
manual TNC31S rev. 'B' (Hardware), DIN-A-4 Winword. (770kB zip)
software-manual TNC3/31 (not up-to-date) (400kB .pdf)
What is KISS and SMACK mode? (Protocol definition TNC <-> PC)
manual old AFSK1200-modem
manual old FSK9600 modem
manual FSK9601 modem
modification instructions for various radios for 9600 Baud use
manual for the TRX4S high speed data transceiver (1.6 MB .pdf)