IP extender is one kind of device to extend the distance over coax cable , twisted pair and telephone line up to 2000m .It applies to security link over coax technology to realize HD IP and SD IP video surveillance by utilizing existed analog system .  This device is used as pair. One is transmitter , the other is receiver. Its another main feature supports up to 60 pieces paralleled transmitters or series connection . So it is easy to networking.  Our device realize upgrading from analog surveillance system to HD IP surveillance easily .