How to Make a DIY Pager Scanner

Female Speaker: It's Monday night at Adafruit headquarters and that means its time for even more hardware hacking. Today I will be completing this part of my pager hack, so if you remember last time we took this Motorola T10 Talkabout pager and we opened it up and we found the RF module and the chip and we found the data sheets so we know what pins are what.

So what I did in the mean time is I soldered a wire to the battery saver line that pager would turn off the RF module once a while and I pulled that high and the data lines so gray and white are the two FSK data lines and black is ground and this pager does four FSKs that's you know four symbols per you know the transition basically and at this moment we are not going to show how to do four FSK interfaces I mean it's still more complicated but if you are cooly just doing two FSK interface, that's pretty easy just basically create a common emitter amplifier using the NPN transistor here, any NPN will do, data into the base through the 1K resistor, we can get power through the serial port here with the simple diode just protect against negative 12 volts and then a pull-up and to get the data out we will actually connect the serial port.

Now one thing that's different about this then most serial protocols is its not 8N1 or 7e1 or you know any sort of RS-232 like serial protocol, its actually 6400 symbols per second and you can't connect it to the Rx lines which you have to bit-bang listen on I think the CTS line you know 6400 times a second to read the data protocol. So just make it clearly that you can use a USB to serial convertor here, you actually have to use a real raw serial port since its being bit-bang.

So this yellow line is the CTS pin going in and you know we can probe on this pin, we can see that there is in fact this data and this is you know about 6 volt peak-to-peak, so looks good and then the serial to my computer and on screen I'm -- a flex decoder software called PDW and basically what happens is every few seconds the RF module even now you know the page is not activated so listening to every page is going over the network that data goes you know through this buffer into the serial port and is translated and displayed on the screen.

So you are probably wondering what kind of pages can you see, well there are actually still a lot of data on the pager network, a lot of emergency notifications actually there are some sport scorers NBA play-off and NHL hockey you see news notifications once in a while but mostly medical and emergency personnel so your weather warnings or disasters or car crashes or you know events happening at your local hospital so even though there is not a lot of personal communications still going on, its still pretty interesting and you know you can definitely spend a couple of hours looking through your pager logs and seeing what's still in the network. So for basically a $10 you get $5 or $10 pager, one dollar in parts and windows computer you can make your own pager.


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