This gets deep, Electronic Design writer says it works….
Louis E. Frenzel says unlocking your car from a cellphone works. This guy is no slouch, check out his bibliography.
“I was skeptical, to say the least, about this rumor, and was about to dismiss it as one more Internet hoax. But I thought I better try it out first. Well, low and behold, it works. I tried it with both GSM and cdma cell phones, and it reliably opens (and relocks) the car.
I have been racking my brain for days about how this works. Two or more different wireless technologies are involved. I even used a 2.4 GHz cordless phone to make the call. The remote keyless entry usually uses on-off-keying (OOK), a form of ASK, to modulate a 315 MHz carrier with the correct serial digital code. Somehow the calling phone picks up this information and transmits it to the receiving cell phone, which then magically retransmits it to the door lock receiver in the car? Yeah, right. “