You know, the fact that the computer choose that moment to perform it's scan doesn't surprise me at all. What does surprise me is "The two [devices] are connected through a serial interface." Who uses serial connectors any more? Are they connecting their monitors vis ISA? Or, perhaps they have the only known MCI cards ever produced?
PS: I have a brand new product for sale: the anti-anti-anti-anti-anti-anti-anti-anti-anti-anti-virus scanner, only slightly used! We'll start the bidding at ten gold doubloons. (That's 10 instances of the word "anti", BTW.)