Audio analog to digital converter

I'm trying to build a converter,with out using a computer to run it.
I'm trying to run an analog siginal into a digital telehpone made by
Motorola-the analog signal out is 120Ω the input to the phone is 50Ω.
the siginal should be filtered before the input.

Most A2D converts require a computer to set them up.

Even if you had a standalone converter it would have to generate an output stream the phone could understand. Some data format/packets.

Or maybe I do not understand what you are doing.