The 'transmit' functionality is very simple. <ESC>| causes the TellyMate to send back the ascii value of the character at the cursor.
It doesn't sound like much, but it means that the contents of the TellyMate screen can be 'read'. This could be a simple way for games to detect walls, other players etc. without having the overhead of storing a copy of the game-screen data on the Arduino.
Having bought my TellyMate shield prior to this latest upgrade, I went ahead to see if I could 'upgrade' to this latest feature. I down loaded the latest firmware zip file and using my USBtiny programmer was able to burn the new hex file as well as fuse settings into a blank mega8 AVR chip.
The board worked as before but didn't seem to be able to utilize the send character feature that the example programs used in the zip file.
The latest user manual mentioned that there was a need for a 'hardware enabled' board to utilize this feature but there is no schematic available yet showing what has changed to enable it.
So I ran one of the example programs and verified with a scope that the new firmware was sending data via the mega8's pin 3 and that pin had no trace going anywhere. So I soldered a short jumper between that pin and pin D0 on the shield's Arduino connector.
Now the example programs work as stated in their comment lines and so that seems like a pretty easy to implement upgrade. If anyone knows if there is more involved with the 'hardware enabled' feature please let us know.
Lefty