List of telephony terminology
This is a list of telephony terminology and acronyms which relate to telephony networks. == A == Advanced Intelligent Network, (AIN), see also IN or Intelligent Network Automatic number announcement circuit (ANAC) Automated Attendant ACD - Automatic Call Distribution Articulation score == B == Blue box - a device that was used to bypass the normal long-distance call switching tones typically used to obtain free calls.
Source: Wikipedia — List of telephony terminology (CC BY-SA 4.0)