3Com S7906E Getting Started Manual page 10

Figure 1-3 Front panel of the S7903E-S
(1) Power modules
(3) Fan tray
(5) Jack for ESD-preventive wrist strap
All modules of the S7903E-S are hot swappable.
The S7903E-S has three horizontal slots. SRPUs are inserted into the upper slot. See callout (2) in
Figure 1-3. Dedicated S7903E-S SRPUs are required. 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 1-4 shows the rear panel of the S7903E-S.
Figure 1-4 Rear panel of the S7903E-S
(1) COM port for monitoring PoE (RS485)
(3) Grounding screws
(4) RTN terminal (+) of external PoE power supply
(5) Negative terminal (–) of external PoE power supply (–46 V to –55 V)
There are two DC power input (PoE power supply input) terminals and two COM ports (monitor ports)
on the rear panel of the chassis.
S7903E
Figure 1-5 shows the front panel of the S7903E.
Figure 1-3.
Figure 1-3. You can select either AC power supply or DC power supply.
(2) SRPUs (in slot 0)
(4) LPUs (in slot 1 and slot 2)
(2) COM port for monitoring PoE (RS232)
1-4
Figure 1-3.