Sony SPP-1000 - Manual (Page 23)

If you use a Private Branch Exchange (PBX)—
You need to dial a digit (such as 9) to access an outside line before
you dial a phone number.
To store the phone number;
1 Enter the outside line access digit.
2 Press REDIAL/PAUSE to enter a pause (to allow the phone
time to access the outside line.)
3 Enter the phone number you want to store.
Note on the power supply--------------------------------
If the battery pack in the cordless handset is completely
discharged, or is removed from the handset for more than several
seconds, the memory dialing numbers stored will be lost. If this
happens, you must store the numbers again.
To keep a directory--------------------------------
Use the directories (supplied). Following is an example of
directory usage.
Write down the names of
persons or places whose
numbers you have stored in
the buttons.
Remove.
Attach back to directory.
becomes hard to hear.
Memory dialing 1 2 3