3Com Hub 1000 SX manual A hub connects to a UPS unit through the hub’s AC power cord

2-10CHAPTER 2: INSTALLING THE HUB

Table 2-4Advanced RPS Configuration Options

Option	Connection	Description
Standard usage	Disconnect the hub’s AC power cable from	The hub obtains DC power from a single
	the AC outlet. Use the straight DC cable	Power Module instead of being powered
	supplied with the Power Module to connect	directly from a standard AC source. If the
	the Power Module directly to the hub	Power Module fails, you can swap the faulty
	through the DC power connector located	module for a new one. This swapping
	on the hub’s rear panel. (See “Rear Panel”	method requires a reset of the hub, as in
	in this chapter.)	a power cycle.
		A cold Power Module supplies power after
		about 5 seconds.
Managed redundancy	Connect the hub’s AC power cable to a	If the Hub 1000 SX internal power supply
	standard AC outlet. Use the straight DC	fails, the hub’s auto-enable feature
	cable supplied with the Power Module to	automatically enables the Advanced RPS
	connect the Power Module directly to the	and resets the hub, as in a power cycle.
	hub through the DC power connector
	located on the hub’s rear panel. (See “Rear
	Panel” in this chapter.)

Full redundancy	Disconnect the hub’s AC power cable from
	the AC outlet. Use a Y DC cable (part
	number 3C16079) to connect the hub
	directly to two Power Modules through the
	DC power connector located on the hub’s
	rear panel. (See “Rear Panel” in this chapter.)

This configuration offers full resilience for mission-critical installations. The hub is powered from both Power Modules instead of being powered directly from a standard AC source. If one of the Power Modules fails, the other module takes the full load. The faulty module can be hot-swapped, returning the system to full redundancy without the need for a power reset.

When switching from Advanced RPS (DC) to AC power or from AC power to Advanced RPS power, the Hub 1000 SX unit resets itself. For example, if both the RPS and AC cables are plugged in, and then either is removed, the unit resets itself when it changes to the other power source.

Uninterruptible The SuperStack II Uninterruptible Power System (UPS) (part number Power System 3C16010, U.S. version) protects against building power outages,

brownouts, power surges, and spikes. If primary power fails or falters for any reason, the UPS automatically provides power for as long as 7 minutes for up to four SuperStack II system units with 100-volt 50/60 Hz, 120-volt 60 Hz, or 230-volt 50/60 Hz power.

A hub connects to a UPS unit through the hub’s AC power cord.