Information terminals

"To this Id has added the ability to have animated messages on the walls, information terminals, access stations, and more."

- Doom press release

Information terminals were a promised feature for Doom that did not end up being implemented in the classic games; waiting until Doom 3 to actually appear officially in the game series.

Animated messages are possible to an extent by using the texture animation functionality. This is quite limited however, and the resolution of the textures makes it difficult to write meaningful messages anyway. For instance, the computer panels depicting the fictional planet Tei Tenga can be read as TCI TCMOR as well as TEI TENGA. Presumably, information terminals – if they had been implemented – would have displayed a special screen, along the line of the conversation screens in Strife, to work around the resolution limitation.

Another limitation of animated textures for messages is that they will simply loop forever. It is possible to change the message by raising or lowering a sector so that the "screen" that shows the message is hidden and another "screen" with another message is shown. However, the player can notice that the configuration of the "screen" has changed, that it has moved forward or backward a bit.

Access stations can be considered to be in the game in the form of switches that open a remote door. The one use in the official levels that does seem to fit the theme of an access station is one of secrets in, where a computer console, if activated, opens up a cache of ammunition and health items.

In source ports
Ports with advanced features, especially level scripting capabilities such as ACS, generally allow to implement the various effects boasted about in the press release. Support for high-resolution textures also allow to make messages on walls more viable.