These are used to make cheap long-distance calls from landlines or mobiles without an internet connection.
The complete guide to PINless calling cards - BOSS Revolution
: Users warn of hidden fees (like maintenance or connection fees) and misleading rates, especially when purchased through hotels. 2. Business/Social "Calling Cards"
: Recommended by users for having competitive rates for calls to mobiles and landlines abroad.
These are physical cards (like business cards) used for networking or social introductions.