Replace a PIC
PICs are housed in the FPCs installed in the front of the router, as shown in Figure 4. Quad-wide PICs, such as the OC-48/STM-16 SONET/SDH PIC, occupy an entire FPC slot and are hot-removable and hot-insertable, as described in Field-Replaceable Units (FRUs). For replacement instructions, see Replace an FPC or Quad-wide PIC.
A regular PIC, which installs into a four-slot FPC card carrier, is hot-removable and hot-insertable in the sense that removing it does not disrupt routing functions; however, you must completely remove its host FPC from the chassis before removing the PIC, which affects all PICs on the FPC.