Podman - I don't know much more about the black boxes.... I suggest you check the compuserve forum and library (Zaurus and connection sections).As for what Nokia told you... probably some jilted high-school cheerleader's part time job. PDA's more often require analog modems, as do the PC Card modems that fit into them. Digital phones are often what is used when they come with a modem in the phone, and/or are being used with an IR connection to the PDA.
But your case is unique because you're trying to use a cell phone with an analog RJ-11 phone jack. Not sure you'll be able to pull it off.
Luck again,
Skyler