Telephones in India:
As a visitor, one can make local, domestic and international calls using the phone from ones hotel room, a public pay phone or using ones cell/mobile phone.
Phones in Hotels: When staying in hotels, please be aware that hotels levy exorbitant charges for making phone calls from rooms. A ten minute international phone call could very well cost $ 100.00.
Public Pay Phones: Public pay phones are plentiful, and all over the country, in the smallest and remotest of villages. You will see them identified with a yellow box and ISD/STD written on this box signifying International Subscriber Dialing (for international calls) or Subscriber Trunk Dialing (for domestic calls). They are invariably manned, meaning there will be an individual who will assist you. You pick up a phone, dial your number and an electronic meter will advise you as to the length of your phone call, and the cost as of that time. When you make all your calls, you pay the individual in cash.
Your Own Mobile Phone: Cell and Mobile phones are very widely used (in fact the number of the above described pay phones are diminishing). If you are a foreign visitor, ask your provider if your phone will work in India. Even if it does work, keep in mind the high cost of international roaming fees for both incoming and out going phone calls. Alternatively, you can bring your own UNLOCKED phone which will allow a “SIM” card to be used, and arrange to get a SIM card when in India. (Note for visitors from the USA: A phone which you have with your provider, say AT&T or T-Mobile which accepts a SIM card will NOT work as this is deemed to be LOCKED to the provider). These SIM cards are easy to obtain from a variety of stores. You will need to bring three passport photographs and your passport. If you are planning to spend a long time in one area, then get the SIM card from that are itself so that your roaming costs are minimized.
Consider buying a local phone in India. Simple minimal function phones can cost about $ 50.00 and then cost of the SIM card is extra. If you do decide to buy a phone in India, note that the cheapest phones will be "Tri-Band" which work in India and some parts of the world. They will NOT work in North America. For them to work in North America, you will need to purchase a "Quad-Band" which will be slightly more expensive, but then you will have the option of replacing your "Indian" SIM card with your "USA" SIM card, and the phone will continue to work.
Phone Numbers: You may see a phone in India which reads, say, +91-11-2345-6789. Here, 91 is India's country code, 11 is the city code (in this case, Delhi is "011"), and then the phone number follows. Do not dial the "0" before the city code if using the "91" country code.
You will also see many numbers like +91-98-123-45678. These are all cell or mobile numbers. Again dial as shown if using the country code, or drop the "91" but add "0" if dialling from inside India, which becomes: 098-123-45678.