It doesn’t take place generally, but just about every at the time in a whilst we stumble upon an individual who has taken obsolete but truly neat cellphone-switching equipment and developed a private switched phone in their garage or basement working with it. This personal analog mobile phone trade is not one of those, but it’s nonetheless a tremendous great build which is possibly about as bold as getting an previous move-by-step or crossbar change working.
Right up entrance, we’ll stipulate that there is unquestionably no simple reason to do anything like this. And hacker [Jon Petter Skagmo] admits that this is extremely much a “because I can” undertaking. The notion is to assist a bunch of previous landline telephones distributed all around the property, and over and above, in a form of glorified intercom procedure. The non-public exchange is totally scratch-constructed, with a PIC32 acting as the coronary heart of the procedure, accomplishing this sort of responsibilities as DTMF decoding, producing ring voltage, and even furnishing a CAN bus interface to his residence automation system.
The principal board supports five line interface daughterboards, which join each and every cellphone to the swap by way of an RJ11 jack. The interface does the function of detecting when a cellphone goes off-hook, and does the real relationship involving any two telephones. A independent, exclusive interface card gives an vehicle-patch capability making use of an RDA1846S RF transceiver module with it, [Jon Petter] can link to any cellular phone in the technique from a UHF helpful-talkie. Look at out the online video underneath for additional on that — it is really neat!
We just like every thing about this overengineered venture — it’s plainly a labor of appreciate, and the in good shape and end definitely mirror that. And even however it’s not strictly aged faculty, POTS assignments like this always set us in the temper to observe the “Speedy Cutover” online video a person far more time.
