Answer The Door via Cell Phone Published by admin on February 23, 2007 | Leave a response “GSM technology is found almost exclusively in cell phones, so why would you ever find it in a doorbell? So your front door can call you when someone rings it, obviously”…. <More> Related posts: Google Switch Touchscreen Mobile Phone – An iPhone Killer? ADEL Biometric Door Lock Cell Phone Pocket Projectors? Apple’s iPhone – the mobile phone, re-invented Emergency Water-Resistant Radio with NOAA, TV-VHF, Flashlight, Siren and Cell Phone Charger. Related posts brought to you by Yet Another Related Posts Plugin.