Chatting is made possible via the RS-MS1A Android app (and the RS-MS1I app for iOS devices). D-STAR capable devices that can connect to these apps via cable or Bluetooth data connection will be able to use this capability.
Android users can choose from the widest variety of radios and connection methods. The list includes 12 radios (as of this writing), four of them Bluetooth capable. For the full list of radios and connection methods, as they evolve over time, check the Function Comparison Chart on the RS-MS1A page of Icom website.
iOS users can choose from 3 radios (as of this writing), all of them Bluetooth. For the full list of radios and connection methods, as they evolve over time, check the Function Comparison Chart on the RS-MS1I page of the Icom website.
If you have an IC-705 or ID-52, you can get started right now with the free app. For other radios, you may need to purchase a Bluetooth upgrade, or a data cable. While a little more expensive, I like the Bluetooth option because it allows you to access and control your radio from outside of your car, there's no cable to stow (and potentially lose or forget).
Once you have the app connected to your supporting radio, simply navigate to the Text Messaging section of the app.
Select a reciever from the list, enter a message, and press Transmit.
A short RF burst will send your message to radios listening via simplex, local repeater, or even via a reflector.
This could be really cool as a regular text-only net with some digital voice just to let those without this capability know what's going on and how to join in. If you'd like to help set something like this up, reach out to me using the info on the feedback portion of this site.
This could also prove an interesting accessability opportunity for those who are speech or hearing impared and can't participate in traditional voice nets. What if instead, they could participate in a net via D-STAR Text Message using equipment they already have?
I also plan to be monitoring the D-STAR 2m simplex calling frequency at events like Hamvention in Dayton, OH when I'm present.
Best of all, as more D-STAR radios start to include Bluetooth data capabilities without the need for upgrade, more and more people will gain this and other capabilities afforded by the free RS-MS1A/RS-MS1I apps to leverage their existing iOS and Android device investment for use in the Amateur radio space.