Today, electronic locks and intercoms technology-Touch Memory ubiquitous. Probably everyone in your pocket, on a bunch of keys is called key-tablet, which is needed to get to the office or in a doorway. Not surprisingly, that many have to carry around all the time on several key tablets, in addition to conventional keys, from which the ligament becomes heavy and cumbersome. As it would be nice to replace the whole bunch of electronic switches for one universal intercom key that opens any intercom! Now you have a chance! By purchasing our universal key, you will forever get rid of all the problems with the keys. You no longer have to freeze under front door and remember the apartment number of your friends to whom you came to visit, you no longer have to call from your mobile and ask you to open an entrance. Universal key to open the intercom is capable of virtually any intercom. So how do you interact with the tablet "base", being a passive device? It should be noted that the parade rules only a master, that is, the tablet is not capable of generating any impulses. Her only opportunity – to keep the tire at zero (close to the ground bus through the internal transistor).
By default intercom is set voltage +5 volts, a la a logical unit. To send a logic zero master through the transistor closes a tire on the ground, and to transfer the unit simply opens. This is done to ensure food slave.