The UT-1 supports the following modes: Transfer mode: transmit images and movies to a host (computer or ftp server) from the camera. In transfer mode, you have the option of turning on Auto Send, which automatically downloads images to the computer/ftp server immediately after they’re recorded to the camera’s memory card. The default setting is OFF; when used, you select images for downloading while in playback mode. PC mode: Transfer images to a computer from the camera directly, instead of saving the images to the media card first, (however, movie files must be saved first to the media card, then downloaded to the computer), as well as control the camera from a computer using Nikon’s Camera Control Pro 2 software.

The UT-1 can store up to nine host and server profiles.

The UT-1 is powered by an EN-EL15 Li-ion rechargeable battery; It can also be powered by the optional EP-5B power connector and EH-5b or EH-5/EH-5a AC Adapter.

The UT-1 attaches to the DSLR via the accessory hot shoe, or the optional SK-7 bracket. To use the UT-1 with a D7100, use the UC-E6 USB cable, which is provided with the camera, to connect the UT-1 with the D7100.

Specifications: Standards: IEEE 802.3u (100 base-TX)/IEEE 802.3 (10 base-T) Data rates: 10/100 Mbps with auto detect Port: 100 base-TX/10 base-T (Auto-MDIX)

Click here for the UT-1 Communication Unit Firmware 2.1 upgrade.