The "red telephone" was never a telephone.
After the Cuban Missile Crisis, the USA and Soviet Union set up the hotline in 1963. It consisted of teleprinters connected by cable via London, Copenhagen, Stockholm and Helsinki. Text, not voice, so translators could check every word and nothing was said in the heat of the moment. The red phone on the desk exists only in films.
Useful: In high-stakes communication, slowness is a feature, not a bug.
Source: en.wikipedia.org