Years ago (1995 to be precise), I had a modem plugged into the airphone that used to be in the headrest of the middle seat on Delta and other airplane seats. I had the phone clicked into the holder, but there was a gap that allowed the cable to snake out to the laptop. As we were waiting for take off, I idly pushed the buttons on the handset and after hitting the # key the screen displayed "dial your number" - this only showed if the modem cable was plugged in and the handset was clicked into the headrest. Although the keypad itself was disabled, it was entirely possible to dial using the modem for a data-only call. Just in case, I switched seats and tried it, connected to my internet provider at that time and everything worked great, albeit at 2.4kbps or whatever it was. I did call up the skyphone folks afterwards and told customer care about it. They were very grateful, but I never heard anything from them and I doubt the backdoor was shut. If anyone worked on that system, I'd like to know if it was left there intentionally or not!