3Com 1000BASE-SX Quick Start Manual page 7

Module Placement in
the Chassis
2-Port 1000BASE-SX and 2-Port 1000BASE-LX Gigabit Ethernet Interface Modules Quick Start Guide
Note the following chassis slot restrictions and recommendations when
you choose a chassis slot for a GEN Interface Module.
In the CoreBuilder 9000 7-slot chassis:
Do not install the module in slot 7. This slot is reserved for a GEN
Switch Fabric Module.
Install the module in slot 1, 2, 3, 4, 5, or 6.
In a CoreBuilder 9000 16-slot chassis:
Do not install the module in slot 8 or 9. These slots are reserved for
GEN Switch Fabric Modules.
To optimize backplane performance, install the module in slot 1, 2,
3, 4, 5, 6, 7, 10, 11, or 12.
3Com recommends that you do not install the module in slot 13,
14, 15, or 16, because these slots only have one connection to the
backplane and the GEN Switch Fabric Modules (see Table 2). If you
install a GEN Interface Module into one of these slots, you can only
use one of the module's front panel ports. The GEN Switch Fabric
Module automatically disables the second port.
Table 1 and Table 2 list the relationship between the 24 Gbps Gigabit
Ethernet (GEN) Switch Fabric Module (3CB9FG24) and the interface
module slots in the 7-slot chassis and the 16-slot chassis, respectively.
Use the information to help select a slot for your module, as well as for
administration purposes after you have completed the installation.
7