NETGEAR FVX538v2 - ProSafe VPN Firewall Dual WAN Reference Manual page 238

ProSafe VPN Firewall 200 FVX538 Reference Manual
Note: The one-time passcode is time synchronized to the authentication server so that
the OTP can only be used once and must be used before the expiration time. If
a user does not use this passcode before it is expired, the user must go through
the request process again to generate a new OTP.
3. The user then proceeds to the Two-Factor Authentication login page and enters the generated
one-time passcode as the login password.
Figure D-3
D-4
v1.0, January 2010
Two Factor Authentication