"North Korea’s state radio has recently broadcast strings of
indecipherable numbers, according to officials in Seoul, in a possible
resumption of a cold war-era method of sending coded messages to spies
operating in South Korea.

A female announcer at the radio station read numbers for two minutes on
24 June and 14 minutes on Friday, according to Seoul’s unification
ministry and national intelligence service (NIS). A copy of those
comments provided by the ministry included phrases such as “No 35 on
Page 459� and “No 55 on Page 913�. [...]"

https://www.theguardian.com/world/20...ers-code-spies

Probably the first time I've seen a number station reported in the
mainstream media.