it is in the manual under attendant features as they are set up by the attendant.

Operation
Press the ON/OFF key.
The phone issues intercom dial tone.
The ON/OFF LED lights.
Press the PROG key.
“F’ appears on the display.
Press AUTO.
“FA” appears on the display.
Enter the Speed Dial code (00-89 or 000-199).
“Enter SSD XX” appears on the display (where “X’ is the System
Speed Dial code).
Dial the telephone number to be stored.
The number appears on the display.
Press the HOLD key.
“SSD XX” (where “XX” is the Speed Dial code) and the stored telephone
number appear on the display.
Repeat steps 2-6 to store additional numbers.


Hope this works out. looks better in the manual.