I think the Ionic forum is not realy the place-to-go to find answers for custom serial communication implementaions.
Anyways, I think you are looking in the wrong direction...
I've never done this particular application, but on a RaspPi I do these things sometimes.
If you would do a google search on "javascript access hardware" you will find
So node.js. is our go-to tool.
http://thinkingonthinking.com/serial-communication-with-nodejs/
You would need to have full control of the device though, to install node.js on your android.
http://www.goland.org/nodejsonandroid/
Try this approach and see if you can get it going...
Good luck