As far as I know the 3400 only ever had ethernet/modem cards available for that slot, though it would be interesting if other cards did exist.
The Orinoco drivers from AlkSoft (direct link to driver page) as mentioned above will work fine with the Wavelan cards, as will the Wavelan drivers from System 7 today. Given that you have OS 8.6 installed, I would recommend the Orinoco 7.2 drivers. The Wavelan Gold can use 128-bit WEP encryption but the Bronzes use no encryption (and the Silvers use 64-bit encryption).
The 3400s are great machines, and the sound out of the four speakers is incredible! I like the screen on mine - it seems so crisp compared to the various passive matrix displays on most of my other PowerBooks.
The Orinoco drivers from AlkSoft (direct link to driver page) as mentioned above will work fine with the Wavelan cards, as will the Wavelan drivers from System 7 today. Given that you have OS 8.6 installed, I would recommend the Orinoco 7.2 drivers. The Wavelan Gold can use 128-bit WEP encryption but the Bronzes use no encryption (and the Silvers use 64-bit encryption).
The 3400s are great machines, and the sound out of the four speakers is incredible! I like the screen on mine - it seems so crisp compared to the various passive matrix displays on most of my other PowerBooks.