ATM

Asynchronous Transfer Mode

CLI

Calling Line Identification

CPP

Calling Party Pays

IN

Intelligent Network

INET

Indian Packet Switched Network

ISD

International Subscriber Dialling

ISDN

Integrated Services Digital Network

ISP

Internet Service Provider

LDCA

Long Distance Charging Area (Usually a revenue District)

POTS

Plain Old Telephone Service

PSDN

Public Switched Data Network

PSTN

Public Switched Telephone Network

SDCA

Short Distance Charging Area (Usually a Taluka)

SSA

Secondary Switching Area (Usually a revenue District)

STD

Subscriber Trunk Dialling