Passphase/passkey config.

I have a laptop running Ubuntu Fiesty, and has been working well, but with some only intermittent issues. I have a Linksys WRT54g wireless router that I have not configured for security (living in a sparse area). I can connect to the router, but it disconnects on occasion, and then I receive requests for a Passphrase, and then a passkey, neither of which I have configured. Are there default settings for these values that I can change later?

I am new to wireless, and it works great. Would love to have it running all of the time, though!

Thanks, and I can supply any information that may be needed to get this configured properly!