- Private Calls are a type of data service. When Private Call traffic is happening, it takes up all the space on each repeater in the network. Some data functions, like APRS-D positioning which does use PC, are fine as they are short bursts of traffic. But Private Calls keep going and stop others from using the network. Private Calls can be even trickier on our MMDVM servers because they usually only have one channel available for most HotSpots.