Which card integrates additional functions without occupying an external modular slot in Cisco routers?

The card that integrates additional functions without occupying an external modular slot in Cisco routers is the AIM, or Advanced Integration Module. AIMs are designed to provide specific functionalities, such as additional packet handling, encryption, or voice processing capabilities, directly within the router without requiring an external slot. This integration allows for a more compact design and enables the router to maintain or expand its capabilities without occupying additional physical space.

Other options like WLCM, VIC, and PVDM serve distinct purposes. For instance, a WLCM (Wireless LAN Controller Module) manages wireless access points but typically requires an external slot. VICs (Voice Interface Cards) are used for voice traffic and also occupy modular slots in routers. PVDM (Packet Voice Digital Signal Processor Module) assists with voice processing tasks but, again, requires specific slots for installation. Thus, the unique feature of AIM modules is their ability to enhance functionality while remaining integrated within the existing architecture of the router.