Nice try, wonder how you expect that to work on Contiki
Of course it would run on TOS, not Contiki.
But from the initial Post, i guess
@mrdweeb is just looking for a way to get his ST online. And STiNG would do that
there is, just search for "tcpser". You run it on a different PC, that is connected to the Atari via Nullmodem, and then connects to some BBS that accepts connections via Telnet. But this is just suitable to connect to such BBS, it is not a general TCP/IP converter.
That is what the PiModem uses. But is there something that runs natively on TOS?
On DOS/PC there is rlfossil, that emulates a serial port over telnet via ethernet. But i don't think you can use a BBS Terminal software to connect to telnet BBS over the netUSBee directly.