I dug up a old 900 MHz Cordless Phone and took it apart. I removed the 900 MHz module and it seems to be hackable. It has the pin spacing similar to Xbees. Both modules seem to be the same except for mounting purposes. I attached high resolution images of the modules. I would like to know if these can be used to transmit any type of data and if so how can I go about doing so.
Thank you for your help.
arduinoPi:
I would like to know if these can be used to transmit any type of data and if so how can I go about doing so.
The first modems had a cradle that the user placed the telephone handset into, used the telephone voice channel.
How do I know which pins on the transmitter/receiver to connect to my Arduino?
I took the phone and read the voltages it send over the pins and I labeled it on an updated version of the image.
I suppose the first thing you need to do is identify the function of the pins, and the second thing is to work out how they're used to power and communicate with the transceiver, and the third thing is to work out how the audio data is encoded when it is presented to the transceiver i.e. whether it's analog or digital, the voltage range or level and so on. It seems to me that you have a substantial amount research to do in order to use this module, and if you aren't familiar with this type of investigation then you are likely to find it difficult. If you are able to spot any identifying marks and find any documentation online to explain how it works, or find anyone else that has already done the investigation for you, then you could avoid a lot of the work. Even so, figuring out how to interface an Arduino to it will still be a substantial undertaking.
Perhaps a simpler option would be to keep the existing electronics intact and have the Arduino drive the audio input (in place of the microphone) and at the far end see if you can tap into an audio output that the Arduino could receive. You'd need to select a suitable encoding scheme - perhaps DMTF would be sufficient.
I assume you're doing this for the sake of doing it, and not because you want a working radio comms solution. There are far more sensible ways to achieve that without repurposing obsolete hardware.
