I've captured a video and telnet session of port 30003 for another example (with the latest ANRB).
http://www.petermcgrath.info/AirNav/blackhole.zipThe aircraft in question is mode-s 7C810C and is is highlighted in both interface and the radar screen (when it is visible on the radar screen)
You can see it in the text interface the entire time of the video.
As the video starts you can see the aircraft approaching the blackhole.
at approx:
18:10 the aircraft stops moving across the radar screen (enters the black hole)
18:16 disappears on the radar screen (GPS parameters disappear)
18:19 aircraft leaves the black hole and re-appears on the radar screen.
Throughout the entire session all parameters (Altitude, GS, heading, vrate etc) are being updated except GPS location, which stops being updated in the "blackhole"