Digimon World DS/Secrets

The System Server
In Digi-central's Accel Room, you can see a pink portal. This is actually the System Server which will reward you if you know the correct password.
 * Password 10407002 - rewards you with DotFalcomon. A special Digimon that possesses the Trait God of Luck. This ability greatly boosts the EXP of all the Digimon in your party after a battle.
 * Password 20000630 - rewards you with DotAgumon. A special Digimon that posseses the Trait Economizer S. This ability significantly decreases the MP used up by skills of all the Digimon in your party during a battle.
 * Password 42016002 - rewards you with Ultimate Swd, Ultimate Brr, and Ultimate Ring. 3 amazing equipment that you can equip on your Digimon to gain a massive stat boost.

References:

For the 3 Passwords: https://retroachievements.org/achievement/168079