The FPCs are hot-insertable and hot-removable. When you remove an FPC, the router continues to function, although the PIC interfaces installed on the FPC being removed no longer function. To replace an FPC, perform the following procedures:
The router holds up to four FPCs, which are installed vertically in the front of the router. An empty FPC weighs 9.0 lb (4.0 kg). A fully configured FPC can weigh up to 12.3 lb (5.6 kg).
To remove an FPC (see Figure 1):
user@host>request chassis fpc slot slot-number offlineFor more information about the command, see the Junos OS System Basics and Services Command Reference.
![]() | Warning: Do not look directly into a fiber-optic transceiver or into the ends of fiber-optic cables. Fiber-optic transceivers and fiber-optic cable connected to a transceiver emit laser light that can damage your eyes. |
![]() | Caution: Do not leave a fiber-optic transceiver uncovered except when inserting or removing cable. The safety cap keeps the port clean and prevents accidental exposure to laser light. |
![]() | Caution: Avoid bending fiber-optic cable beyond its minimum bend radius. An arc smaller than a few inches in diameter can damage the cable and cause problems that are difficult to diagnose. |
![]() | Caution: The weight of the FPC is concentrated in the back end. Be prepared to accept the full weight—up to 12.3 lb (5.6 kg)—as you slide the FPC out of the chassis. When the FPC is out of the chassis, do not hold it by the ejector handles, bus bars, or edge connectors. They cannot support its weight. Do not stack FPCs on top of one another after removal. Place each one individually in an electrostatic bag or on its own antistatic mat on a flat, stable surface. |
![]() | Caution: After removing an FPC from the chassis, wait at least 30 seconds before reinserting it, removing an FPC from a different slot, or inserting an FPC into a different slot. |
Figure 1: Removing an M120 FPC

To install an FPC (see Figure 2 and Figure 3):
![]() | Caution: When the FPC is out of the chassis, do not hold it by the ejector handles, bus bars, or edge connectors. They cannot support its weight. |
![]() | Warning: Do not look directly into a fiber-optic transceiver or into the ends of fiber-optic cables. Fiber-optic transceivers and fiber-optic cable connected to a transceiver emit laser light that can damage your eyes. |
![]() | Caution: Do not let fiber-optic cable hang free from the connector. Do not allow fastened loops of cable to dangle, which stresses the cable at the fastening point. |
![]() | Caution: Avoid bending fiber-optic cable beyond its minimum bend radius. An arc smaller than a few inches in diameter can damage the cable and cause problems that are difficult to diagnose. |
user@host>request chassis fpc slot slot-number onlineFor more information about the command, see the Junos OS System Basics and Services Command Reference.
![]() | Caution: After the OK LED lights steadily, wait at least 30 seconds before removing the FPC again, removing an FPC from a different slot, or inserting an FPC in a different slot. |
You can also verify correct FPC and PIC functioning by issuing the show chassis fpc and show chassis fpc pic-status commands described in Maintaining M120 FPCs and CFPCs and Maintaining M120 PICs and PIC Cables.
Figure 2: Installing an M120 FPC

Figure 3: Connecting Fiber-Optic Cable to an M120 PIC
