ZyXEL Communications GS1900-8 User Manual page 108

Table 66 Configuration > Port > PoE > Port > Edit (continued)
LABEL DESCRIPTION
PD Priority This field is not available for the SFP or SFP+ ports.
When the total power requested by the PDs exceeds the total PoE power budget on the
Switch, you can set the PD priority to allow the Switch to provide power to ports with higher
priority.
Select Critical to give the PD connected to this port the highest priority.
Select High to set the Switch to assign the remaining power to the port after all critical
priority ports are served.
Select Low to set the Switch to assign the remaining power to the port after all critical and
high priority ports are served.
Power-Up Set how the Switch provides power to a connected PD at power-up.
802.3af - the Switch follows the IEEE 802.3af Power over Ethernet standard to supply
power to the connected PDs during power-up.
Legacy - the Switch can provide power to the connected PDs that require high inrush
currents at power-up.
Pre-802.3at - the Switch initially offers power on the port according to the IEEE 802.3af
standard, and then switches to support the IEEE 802.3at standard within 75 milliseconds
after a PD is connected to the port. Select this option if the Switch is performing 2-event
Layer-1 classification (PoE+ hardware classification) or the connected PD is NOT performing
Layer 2 power classification using Link Layer Discovery Protocol (LLDP).
802.3at - the Switch supports the IEEE 802.3at High Power over Ethernet standard and
can supply power of up to 30W per Ethernet port. IEEE 802.3at is also known as PoE+ or
PoE Plus. An IEEE 802.3at compatible device is referred to as Type 2. Power Class 4 (High
Power) can only be used by Type 2 devices. If the connected PD requires a Class 4 current
when it is turned on, it will be powered up in this mode.
Wide Range This field is available on GS1900-8HP (Revision B1) and GS1900-10HP only.
Detection
Select whether to enable a wider detection range for the PD or not.
The Switch detects whether a connected device is a powered device or not before supplying
power to the port. For the PD detection, the Switch applies a fixed voltage to the device and
then receives returned current. If the returned current is within the IEEE 802.3AF/AT
standard range, the device will be considered as a valid PD by the Switch.
However, in real cases, environmental interferences might easily cause the returned current
out of the standard range. This field displays Enable if the Switch applies a wider range for
PD detection. Otherwise, it displays Disable.
Apply Click Apply to save the changes.
Cancel Click Cancel to discard the changes.
Chapter 19 Configuration: Port
GS1900 Series User's Guide
108