Midspans
Midspan or Endspan
Power over Ethernet (PoE) is the designation used for power transfer via a standard Cat. 5/6 twisted pair cable, and not only allows for the saving of the additional mains power line but also, thanks to the safe low voltage, can be laid by a non-professional. PoE works with voltages of less than 60 V and is therefore classified as SELV (Safety Extra Low Voltage). A distinction is drawn between injectors (PSE – Power Sourcing Equipment), which in turn can be designed as Midspan or Endspan and consumers (PD-Powered Device).
Midspans use the spare pairs 4|5 und 7|8, endspans transmit power only over the data line pairs 1|2 und 3| 6. It is possible for ageing networks to apply power to an existing Ethernet switch using midspan hubs. There are 4,8,16 and more channels to choose from here, with outputs of up to 90W per port, mostly available as 19" rack units with 1U height.
Samples Contacts NewsThree Power Classes According to IEEE
- IEEE802.3af (15.4 W per port)
- IEEE802.3at (30 W per port)
- IEEE802.3bt (up to 90W per port)
Special Classes
- Ultra PoE with 60W per port
- Mega PoE with 95W per port
