Panasonic S-ICX Technical Manual page 178

Chapter 5. Key Telephone Features Section 700 - Operation
b. Press the fourth FF key from the left on the bottom row.
To enter o:
a. Press the third soft key from the top right.
b. Press the third FF key from the left on the bottom row.
5-80 ICX (International) issued December 1999 ICX-40-700