Recently I am working on letting calculators send messages to each others. And I own four Argon chips which are the 3rd Gen of Photon.
I have cut my TRS wire, the Tip connect to D6, the ring connect to D5
My Idea is type SSID and Password into my TI-84+ Silver, then using I/O port read pin to send those two to Argon, then the Argon would connect to the WIFI.

Then, When CalcA sends Text, it also will use I/O write pin, and Argon would get the Text then send to other Argons.

Other Argons will receive the Text, using write pin send the Texts to Calcs

The problem is, it looks pins could only read and write some VERY UNSTABLE voltages, but cannot transport data. What should I do? I have seemed Kerm's project of gCn, so I think pins should be able to send data.

It sounds like you just want to use my Spark Core gCn driver + CALCnet Chat! to me?

I definitely tried, but there is a lot of problems(I posted in my last thread)... I want to know how to use the pin on the spark core to send strings to my calculator.

Now I am able to send 4 different letters(or numbers), by setting the ring or tip is HIGH or LOW.
But that is not enough obviously
[youtube]https://youtu.be/BwWlNCA58qE[/youtube]
But I still believe the I/O port is able to transport more complex data... but in what way?

By sending sequences of 8-bits one after the other.