No. The Apple Thunderbolt Monitor does not provide power to a Thunderbolt device connected to the captive cable, and consequently does not support bus-powered devices (like the Echo ExpressCard/34 Thunderbolt Adapter) connected to the captive cable. Apple instructs in their manual to connect the Apple Thunderbolt Monitor's captive cable to a Thunderbolt computer, and to connect Thunderbolt peripherals to the Thuderbolt port using a detachable Thuderbolt cable.