Video Transmission

The SIAMnet may also be used by an operator, located at the Control Room, to view selected areas inside the mine.  The SIAMnet has the capability to carry video signals from a camera up to the Control Room using conventional CATV and CCTV equipment.

The number of cameras concurrently sending real-time images depends on the Modulator type selected and the use of the Data Channel bandwidth in function.

CCTV Camera

The SIAMnet allows up to five TV channels to operate continuously and in real-time. 

However, in a particular application, when not all SRM channels are used, the available bandwidth may be used for additional video transmission channels.

At the Head-end, demodulators are used to extract the video image from the DAS. CCTV multiplexors and monitors may be used to display all the camera images to the operator in the control room. In a simple camera application, a conventional television may be used.

Control Room CCTV Equipment
Operator selecting the scene to be viewed at the Control Room

The operator uses the keyboard to select the camera he wishes to view in full screen mode. 

He may also visualize 2, 4, 9 or 16 cameras at one time by using those split screen options.

In large mines, where the SIAMnet is divided into branches at the Head-end, the maximum number of cameras is multiplied by the number of branches.

For example, a 4 branch SIAMnet may support 40 cameras in real-time. More cameras may be monitored by the control room operator if using cameras with built-in title display. Actually, a single channel is required for those applications where only one camera is active at one time.