Be certain to verify the number of minutes the card will cover for various types of calls. It is not very practical to use phone cards for international calls which tend to be very expensive. At a P.C.O. an attendant will time the call and then the caller pays the attendant. To avoid surprises ask ahead how much a call of a certain length and to a destination will be.
International calls are very difficult and expensive to make.
In general it is best to rely on e-mail since internet cafes are common. It is not possible to make collect calls to or from Pakistan. Because wrong numbers are common, many phone conversations start by verifying whether one has the correct number or establishment. When one is already acquainted with the members of a household, it is polite to carry on a brief conversation about the family's well-being before asking for whomever one is calling.