Weird icon at the top right corner of the phone

[JakubRWrobel]

The image above shows an icon at the top right corner of the screen (directly to the left of the battery percentage) and I have no idea what it is. It looks like a phone above a keyboard. I looked in the Accessibility menu, but I couldn't see any option that could represent this.

Anyone have an idea what this could be? The phone is on a Verizon network.

Any help is welcome.

Thanks.

 

[Ledsteplin]

TTY symbol.
https://support.apple.com/en-us/HT201906

 

[JakubRWrobel]

TTY symbol.
https://support.apple.com/en-us/HT201906

Thank you! Problem solved.