Class B itinerant pulsar

A class B pulsar or cyclic pulsar was a classification of pulsar used by Starfleet.

The USS Voyager passed an itinerant class B pulsar with a rotation cycle that peaked for seventeen hours every 32 days, in the Delta Quadrant in late 2376. Pathfinder Project used the opportunity to use the MIDAS array to amplify the signal of a communication through the pulsar so it could reach Voyager some 30,000 light years away, in the form of a compressed data stream. This allowed for them to send each other quick bursts of information (such as letters and tactical updates) every 32 days, giving Voyager seventeen hours to respond. 

After Voyager had passed the pulsar, Starfleet still used it to amplify the signal of a data stream every 32 days until early-2378 when Operation Watson bounced the signal off a quantum singularity instead.