Noble friend of all those who seek network access from telephone booths, truckstops, and roadside attractions, the Acoustic Koupler is always ready to deliver a quick email fix or maybe just a minor FTP session from the Plaid Pantry parking lot.
Or maybe you're an oldtimer, gone all misty-eyed for the halcyon days of 2400bps access. Just give that payphone's handset a sharp little knock to activate that cheapo carbon microphone, velcro that sucker on up with the Koupler, and wire it back to your modem. Now you're ready for some remote connectivity.