where can i get a digital to analog convertor for my phone line for this...

[jeramy]

...scram modem/moniter thing? I've just been placed on the scram bracelet and its not yet been activated but the woman who put it on me said i needed a converter for the phone line top go from digital to analog. I've been to radioshack, walmart, bestbuy and looked online but don't really understand what i need to get