The ISV3 is Huawei OptiX RTN 980 IDU Versatile IF board
ISV3 boards are multi-purpose IF boards that support Integrated IP microwave and SDH microwave, as well as DC-I power distribution. Once the appropriate license files are loaded, the boards also support cross polarization interference cancellation (XPIC). ISV3 boards apply to long- and short-haul microwave service transmission.
The functional version of ISV3 boards is SL91 and it's Versatile IF board
Application
ISV3 boards apply to long- and short-haul microwave service transmission. They can function as SDH IF boards to transmit SDH microwave services, or as integrated IP microwave IF boards to transmit integrated IP microwave services (Native E1+Ethernet or Native STM-1+Ethernet). To increase transmission capacity, ISV3 boards can also support the XPIC function.
Functioning as SDH IF Boards
If applied to OptiX RTN 980L NEs building TDM microwave networks, ISV3 boards function as large-capacity SDH IF boards to transmit TDM services
Functioning as Integrated IP microwave IF Boards
ISV3 boards apply to Integrated IP microwave NEs to transmit one or more of the following services: Native E1 services, Native STM-1 services, Native Ethernet services, and MPLS/PWE3 services