Patch Panels, PoE Injectors and LAN Adapters

PoE injectors: match the standard and the wattage

An injector adds power to an Ethernet cable for a device with no nearby outlet. Standards-based PoE comes as 802.3af at 15.4 W, 802.3at (PoE+) at 30 W and 802.3bt at higher power, and the device must need no more than the injector offers. Some injectors use passive power at a fixed voltage such as 24 V, which is not standard PoE: a standard device may not power up, and equipment not designed for that voltage can be damaged. Confirm that injector and device use the same method, and that the cable run stays within the 100 meter Ethernet limit.

Patch panels, converters and USB LAN adapters

Patch panels come in 24 and 48-port versions for 19-inch racks, loaded with jacks or blank keystone types that take the jacks you choose, in shielded or unshielded form to match your cable. Media converters link fiber to copper, so match the fiber mode and the SC or LC connector at both ends. USB LAN adapters need USB 3.0 for gigabit; the USB-C or USB-A plug must fit your port, and driver support for your operating system is worth checking.

Questions about Patch Panels, PoE Injectors and LAN Adapters

Do I need an injector if my switch has PoE?

No. A PoE switch powers devices directly, within its power budget. An injector is for non-PoE switches, for a single remote device, or for when the switch has run out of PoE capacity.

Will a USB 3.0 Ethernet adapter reach gigabit on a USB 2.0 port?

It will usually work, but slower. USB 2.0 tops out at 480 Mbit/s before overhead, so you will not see full gigabit speed. Use a USB 3.0 or USB-C port with a gigabit adapter for the full rate.

What do keystone and blank mean on a patch panel?

A blank keystone panel has empty slots that accept individual jacks you choose, such as shielded or Cat6a types. A loaded panel comes with ports already fitted. Blank panels give flexibility; loaded ones are quicker to install.