i own a GE interlogix kalatel VDR. it is hooked up to mutliplexor (AVC 713 B/W quad processor). i have four cameras hooked up with one monitor. when i have it set on 1 camera and/or the "quad" setting so the screen is showing all four cameras...as it records in this mode everything is fine. i found out by accident when i have it on "switch" mode (cycling through all four cameras)..and visible that way (a split quad screen) on monitor...the DVR will intermittently stop recording and makes an annoying beeping noise..on the monitor as it stops recording will be a visible gray screen only showing version and disk size of the VDR ..then it goes away...and starts recording again. it will continue this randomly until i put the multiplexor back on "quad" or one camera setting. i would greatly appreciate any reply/help on this matter.