Mitel MiVOICE BUSINESS, Engineering Manualline

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Engineering Guidelines
92
MIVOICE IP PHONE POWER
PoE (Power over Ethernet) is a method of providing power to the phones over the existing
Ethernet wiring that the phones use for connecting to the LAN.
MiVoice IP Phones support 802.3af power over Ethernet. With the exception of the 3300 CXi/CXi
II ICP, power provisioning to the IP phones is not provided from the 3300 controllers. For details
regarding power provisioning from the CXi and CXi II, refer to “3300 CXi/CXi II ICP 802.3af
Power over Ethernet capabilities” on page 97.
Power can be provided to the phones either locally by an AC power adapter or remotely by a
network device that supports PoE.
LOCAL PHONE POWERING
Phones can be powered locally with the following methods (depending on the model):
• With an AC power adapter that converts mains voltage into the 24VDC required by the
phone.
• With a special in-line Ethernet power adapter that provides a local power feed to the Mitel
5000, 5200, and 5300 series of IP phones. This adapter converts mains voltage into -48
VDC and supplies power to the phone over the Ethernet cable.
REMOTE PHONE POWERING
Phones can use one of three different communication standards to advertise their power
requirements to a powered Ethernet switch. In all cases both the phones and the powered
Ethernet switch must comply with the same standard. The three standards are:
1. IEEE 802.3af Power Over Ethernet Standard (PoE)
2. IEEE 802.3ab Link layer Discovery Protocol (LLDP-MED)
3. Cisco Discovery Protocol (CDP)
To determine which standard(s) a particular phone supports refer to Table 32.
Phones can be powered remotely with the following methods:
• If the phone supports the IEEE 802.3af power over Ethernet standard, remote power to the
phone can be supplied by an IEEE 802.3af compliant Ethernet switch. Alternately, if the
phone and the powered Ethernet switch both support LLDP-MED, then the phone can
advertise its power requirements to the IEEE 802.3ab compliant switch.
• If the phone supports the IEEE 802.3af power over Ethernet standard, but the Ethernet
switch does not support the IEEE 802.3af power standard, a midspan IEEE 802.3af power
hub can be used to remotely supply power to the phone over the Ethernet cabling. The
mid-span power hub resides between the Ethernet switch (which in this case does not
support IEEE 802.3af) and the phone.