It depends on how you're planning on powering the unit. If you're expecting to feed standard AC power to the unit, you need the first one. If you need to power it from a DC source, you need the second one.
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Jody Lemoine, Network Architect
CCIE 41436, MTCRE, MTCINE, MTCIPv6E
tishco networks, Virtually Everywhere
(905) 378-1134, jody.lemoine@tishco.ca