As Cloudschatze already indicated, your Voyetra card is most definitely MPU-401 Intelligent Mode and UART compatible. It probably does need the breakout box, although I suppose that it's possible for someone to have worked out the pinout for the connector for a homebrew version. For instance, there isn't any real trickery for the breakout box for the Roland Super MPU - all of the logic is on the card, and the breakout box is just a series of connectors, traces, and a few coupling caps, IIRC. Ditto for the connectors on the Music Quest MQX-32m and the Midiman MM-401 full MPU-401 cards.
You might want to use Google to search Quest Forums and Vogon's in case someone has already done the work. Alternately, put up a post there and see who bites!