Snom 220 - Manual (Page 15)

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15
The default mode for password input is integer. You can switch to other
input modes by pressing , , or . The password is hidden
and replaced by a series of *s to keep it hidden from prying eyes.
Repeat the same procedure for all accounts with authentication. The
challenge responses are stored in the phone and will be used at re-
registration or on reboot. You can also edit this information via the web
interface.