Pennywhistle modem
... that Lee Felsenstein designed the Pennywhistle modem to replace a commercial design used on Community Memory, the first bulletin board system?
... that <a href="./Lee_Felsenstein" id="mwCOk" rel="mw:WikiLink" title="Lee Felsenstein">Lee Felsenstein</a> designed the <b id="mwCOo"><a href="./Pennywhistle_modem" id="mwCOs" rel="mw:WikiLink" title="Pennywhistle modem">Pennywhistle modem</a></b> to replace a commercial design used on <a href="./Community_Memory" id="mwCOw" rel="mw:WikiLink" title="Community Memory">Community Memory</a>, the first <a href="./Bulletin_board_system" id="mwCO0" rel="mw:WikiLink" title="Bulletin board system">bulletin board system</a>?