Power supply units Cisco

The Cisco® Catalyst® 4500 E-Series platform offers line cards, power supplies, and accessories (including an AC power shelf) to support 15.4W per port simultaneously on every port in any fully loaded Cisco Catalyst 4500 E-Series switch. Although all references to "Power over Ethernet" (PoE), "inline power," and "voice" power supply and line cards are synonymous, there are three versions: Cisco prestandard PoE, 802.3af-compliant PoE and PoEP (30W). Every Cisco Catalyst 4500 Series chassis and PoE power supply supports the IEEE 802.3af standard, the Cisco prestandard and PoEP power implementation, helping ensure backward compatibility with existing Cisco powered devices. PoEP is standard on Cisco Catalyst 4500 E-Series platform.

All Cisco Catalyst 4500 Series PoE line cards can distinguish an IEEE or Cisco prestandard powered device from an unpowered network interface card (NIC) to help ensure that power is applied only when an appropriate device is connected. With a Cisco PoE network, administrators can depend on a robust network that is safe to deploy and simple to maintain.

PoE(P)
PoE provides -48-VDC power over standard Category 5 unshielded twisted-pair (UTP) cable up to 100 meters when an IEEE 802.3 af-compliant or Cisco prestandard powered device is attached to the PoE line-card port. Instead of requiring wall power, attached devices such as IP phones, wireless base stations, video cameras, and other IEEE-compliant appliances can use power provided from the Cisco Catalyst 4500 Series PoE line cards. This capability gives network administrators centralized control over power and eliminates the need to install outlets in ceilings and other out-of-the-way places where a powered device can be installed. When a switch is connected to an uninterruptible-power-supply (UPS) system, network administrators can ensure that power outages will not affect network availability. PoEP extends the power over ethernet cable to up to 30W per port.