Asynchronous data transmission using FSK

Hi,

I have asynchronous binary output that changes from -5V to 5V (It is changable). Can someone suggest me module or chip or open source approach to send and receve this signal using Frequency Shift Keying (FSK)?

If there is some other modulation approach, it would be very helpfull too.

The main idea is to send Asynchronous data.

In this picture, with blue colour you can see asynchronous output that changes depending on input signal and it can switch side in any momemnt:



Thanks for your time and answers