Network cheat mode -
Hold [Alt] and type "iddtiddtiddtiddt" in map mode.

Deathmatch cheat mode -
Press T in the map to enter talk mode. Then, hold [Alt] and type "iddt" several 
times. This will reveal the entire map. Repeat the code to reveal all items. 
Repeating the code again will return the map to normal.

Cheat Codes -
While playing a game, enter one of the following codes to activate the 
corresponding cheat function:

Result - Cheat
Invincibility - iddqd 
All weapons, keys, ammo, and 200% armor - idkfa 
Reset ammunition - idfa 
Berserker strength - idbeholds 
Temporary invincibility - idbeholdv 
Temporary invisibility - idbeholdi 
Full automap - idbeholda 
Anti-radiation suit - idbeholdr 
Light amplification visor - idbeholdl 
Walk through walls - idclip 
Chainsaw - idchoppers 
Level select - idclev[level number 01-32] 
Toggle full map; full map and objects; normal map - iddt 
Display coordinates and heading - idmypos 
Change music to indicated level - idmus[level number 01-32] 
Kill all enemies in level - fhhall 
Invisible to enemies until attack - fhshh