I made a texting software using C language and using two zigbees by configuring their address and then sending messages from one zigbee to the other in turns.
The address of each zigbee is set up by the help of DIP Switches and pushbuttons on the motherboard which I had soldered in my engineering class at UW-Madison.
Then the characters can be scrolled through with the help of a potentiometer and a pushbutton can be used to select the character (which appear on a screen attached on the motherboard).
A certain pushbutton sends the message constructed. Another pushbutton switches between the sending and receiving mode. The message is received by the other person and the process starts from the other end all over again.