3Com S7906E Getting Started Manual page 8

The backplane, switching & routing processing unit (SRPU), power modules, and fan tray are all
required parts of the S7900E series.
SRPUs and line processing units (LPUs) are distinguished by their edge colors. SRPUs have pink
edges while LPUs have purple edges. SRPUs must be inserted in pink slots while LPUs must be
inserted in purple slots.
The power supply of the S7900E series can be AC or DC, depending on the actual requirement.
However, it is forbidden to insert different power modules into one S7900E Ethernet switch.
S7902E
Figure 1-1 shows the front panel of the S7902E.
Figure 1-1 Front panel of the S7902E
(1) Power modules
(3) Fan tray
(5) Jack for ESD-preventive wrist strap
All modules of the S7902E are hot swappable.
The S7902E has four horizontal slots. SRPUs are inserted into the upper two slots. See callout (2)
in Figure 1-1. SRPUs are required and support active-standby switchover. Different LPUs are
inserted into the other two slots. See callout (4) in
The fan tray is installed on the right side of the chassis. See callout (3) in
The two power modules, which sit in the upper part of the chassis provide 1+1 redundancy backup.
See callout (1) in
Figure 1-2 shows the rear panel of the S7902E.
Figure 1-1. You can select either AC power supply or DC power supply.
(2) SRPUs (in slot 0 and slot 1)
(4) LPUs (in slot 2 and slot 3)
Figure 1-1.
1-2
Figure 1-1.