Specifications
10 Installing the Hardware
Supplying Power
Supply power to each S25P in a stack only after each switch is mounted and the stack ports are connected.
There is no on/off switch, and the stack members partly determine the stack management unit from the
order in which they come online (see above).
The S25P switch (catalog # S25-01-GE-24P) has two AC receptacles in the rear of the chassis (see
Figure 2 on page 9). The system can use either power source independently or in combination, in active/
backup mode. Connect the supplied AC power cord first to either receptacle of the S25P (on the right as
you face the rear of the chassis) and then to the power source (see AC Power Requirements on page 32).
Ensure that the cord is secure. If you connect both AC power supplies, ideally you would connect them to
separate circuits.
S25P-DC
Figure 3 The S25P-DC Rear View
As shown above, the S25P-DC (catalog # S25-01-GE-24P-DC) has two DC terminal blocks on the right side.
You can supply power to either one or both, in active/backup mode (no precedence for either). The terminal
block on the left corresponds to the DC2 status LED on the front left of the switch; DC1 is on the right.
You must provide your own cables to connect to the power source. Cables must be sized for 11.5 A service
at -48VDC input (per NEC in the United States. Internationally, follow local safety codes.) Before you
make the cable connections, apply a coat of antioxidant paste to unplated metal contact surfaces. File
unplated connectors, braided straps, and bus bars to a shiny finish.
1. Make sure that the remote power source (the circuit breaker panel) is in the OFF position.
2. Remove the safety cover from the DC terminal block.
3. Connect the grounding cable to the FG terminal first, then connect the opposite end to the appropriate
grounding point at your site to ensure an adequate chassis ground.
4. Connect the -48 V and -48 V RTN (Return) cables to the switch terminals and then to the remote
power sources, ideally on separate circuit breakers.
5. Replace the safety covers on the DC terminal blocks.
6. When connecting both terminal blocks, do not supply power until both are connected.
fn00158s25P-DC
10-Gigabit Modules or Stacking Modules (optional).
Optical ports numbered from left to right.
DC2
Ground Connector
DC1
(, , , , )
Ethernet Port Numbers
25 to 28, Right to Left
FG
-48V
RTN
-48V
FG
-48V
RTN
-48V