Unkonwn QBus card... anybody know what this is?

Hi, all! I recently purchased a large batch of old QBus cards to expand some of the systems in my collection, and one of the cards in the batch is rather unknown to me... I know its some kind of disk controller, guessing MSCP ST-506 but I'm wondering if its SCSI because i'm seeing some resistor packs on the board that could be terminating resistors, I suppose... anyways, here's the information: (Label on top of large 48 pin IC) "TD Systems Inc. Lowell, MA - USA VIK/QDT #2111" (Label on 28 pin ROM) "Viking Q/B A4.0" (Etching on card component side) "211 00031 Rev. E" (Another etching on component side) "(C) 1987 Made in USA Assy 210-00031" Physical characteristics - dual width board, 50 pin connector on board with a single red LED near the connector. I'd appreciate it if someone could clue me in on the identity of the card - i'm rather curious as to what it is! :) Thanks, -Sean Caron (root(a)diablonet.net)