Aastra M401 User Manual page 43

Customizing your phone
Select the feature type you wish to program
Dial the code you want to assign to that feature (see p.44)
Press the key to validate the operation.
Hang up.
THE MOST COMMONLY USED PROGRAMMED FUNCTIONS ARE:
Type 1 : storing internal and external numbers.
Type 3 : programming DTMF (touchtone) codes (for direct access to voice mail,
for example).
TYPE
CODE
42