Defining Softkeys
You can customize the keyboard so that you can include special characters such as the symbol for degree ° and the Greek character "phi" in your prefix:
1. Define the softkey [f1] to degree symbol °:
Enter DEFINE_KEY 1 (CHR 179) and press [Enter].
2. Define the softkey [f2] to "phi":
Enter DEFINE_KEY 2 (CHR 210) and press [Enter].
Now whenever you press the appropriate softkey you can include the required symbol in your prefix.