Siemens HiPath 4000 Operating Instructions Manual page 30

Telephone settings
Step by Step
rhm
or
or
or
Enter the code!
30
Enabling the telephone again:
n
Lift the handset.
rel
UK code or Standard code
rmf
Euro code
Enter the code which has been programmed for you.
and
p
Enter the PIN (code number).
t
Replace the handset.