Abstract: A multiplexor is designed to receive data from a plurality of data sources. As the multiplexor receives data from data sources, its programmable logic device codes each stream of data with a header and a footer and a data stream segment between them having a prescribed number of characters. A message from any particular data source may be coded into a plurality of separate data stream segments. The multiplexor sequences to the next data source when a data stream having the prescribed number of bytes has been captured and returns to that data source only after data streams of the same prescribed number of characters have been captured from the other data sources in a sequential manner. Data so coded is forwarded to a storage device that may store the data on any suitable storage medium for later retrieval.

Abstract: An image recording system and method for use with a surveillance system having at least two cameras provides true pre-event recording for multiple input sources to improve video on demand storage control. More specifically, an image recording subsystem is connected to the cameras for receiving generated video images, and storing the received images in a temporary storage device having a storage capacity large enough to store video images generated over a predetermined period of time. The image recording subsystem is arranged to continuously record video images into the temporary storage device such as a cache memory, and in response to the occurrence of a triggering event, subsequently record the temporarily stored video images into a long-term storage device for later retrieval.