3Com 3C16894 4-slot Chassis manual Power Module, Power Distribution, External PoE Power, System

Power Module 33

Table 43 Specifications for the 8-Port10/100/1000BASE-T GE Module (continued)

Specification	Description
Port transmission speed	10 Mbps, half/full duplex
	100 Mbps, half/full duplex
	1000 Mbps, full duplex
Cables and maximum	4 100-ohm Category-5 non-shielded twisted pairs up to 100
transmission distance	m (300 ft).
Compliance	IEEE 802.3ab
	IEEE802.3
	IEEE802.3u
	IEEE802.3x

Power Module	Only one AC power module is required for the 4-slot chassis, although two power
	module slots are provided to implement N+1 redundancy.
	The 7-slot and 8-slot chassis provides three power module slots to implement N+1
	redundancy. However, two power modules are sufficient to power one of these
	fully loaded Switch 7700 systems.
	The 8-slot chassis offers both AC and DC power modules. Table 44 describes the
	specifications of each type of power module.
	Table 44 Specifications for AC and DC Power Modules
	Specification	AC Power Module	DC Power Module
	Input	100 V to 240 V, 47 to 63 Hz	-48 V to -60 V
	Maximum output	460 W	460 W
Power Distribution	The Switch 7750 power distribution box is installed on the chassis floor in the back
	of the chassis. It filters, connects, disconnects, and distributes electrical current to
	the switch.
	The power distribution box for the 4-slot chassis has two inputs and each input
	has a separate ON/OFF switch. One input can support the normal operation of one
	power module. Both AC inputs must be connected and switched on to provide
	power to both power modules and to offer N+1 AC power redundancy. When
	two power modules are installed but only one AC power input is working, only
	one power module will operate. However, the power module LEDs on the Fabric
	display alarm information for the power module that is not working.
	The power distribution box for the 7-slot and 8-slot chassis has two inputs and
	two ON/OFF switches. One input can support the normal operation of three AC
	power modules at the same time. When both AC power inputs are connected and
	switched on, the power distribution box offers N+1 AC power redundancy.
External PoE Power	The Switch 7750 supports power-over-Ethernet (PoE). When the Switch 7750 is
System	equipped with an external PoE power system and PoE-capable I/O modules, it can
	provide -48 V DC power to remote powered devices (PDs), such as IP phones,
	WLAN APs, and network cameras through twisted pair cable.

Figure 30 illustrates the Switch 7750 PoE power system.