The Ports tab displays a list of the current port service mappings, and lets you enable or disable UPnP port forwarding. To enable or disable UPnP port forwarding: Set UPnP port forwarding to ON to allow UPnP devices on your Fiber network to set their own port forwarding rules.
VRML (Virtual Reality Modeling Language) is a language for describing three-dimensional (3-D) image sequences and possible user interactions to go with them.
VRF (variable refrigerant flow) or VRV (variable refrigerant volume) comfort systems consist of multiple evaporators with variable capacity, connected to one central variable-capacity inverter-driven heat pump. These systems feature a heat-recovery mode that allows the transfer of energy from zone to zone with minimal compressor use.