PICs provide the physical connection to various network media types. PICs receive incoming packets from the network and transmit outgoing packets to the network. During this process, each PIC performs framing and line-speed signaling for its media type. Before transmitting outgoing data packets, the PICs encapsulate the packets received from other router components. Each PIC is equipped with a media-specific ASIC that performs control functions tailored to the PIC's media type.
On the M7i and M10i routers, PICs are installed directly into FPCs that are built in to the chassis. (These FPCs cannot be removed from the chassis.) On the M40e, M120, M320, and T320 routers and the T640 and T1600 routing nodes, PICs are installed into Flexible PIC Concentrators (FPCs) that are plugged into the chassis.