Now that you don’t have to wonder how does callback work?, I can explain some of the interesting designs that comes with this system. By designs, I am refering to so-calls “hacks” or modification made to the original system to support a particular type of users or a new functionality. As callback was an competing alternative to the traditional phone service, it is usually not well received by the national phone operators in most of the countries where it is the most widely used.

So, following a related post by Julian Bleecker (Mobile Phone Usage Idiom — No. 2) and a Times article, Phone revolution makes Africa upwardly mobile , I felt it would be timely to describe one such hack used for mobile phones in some part of Africa.

As I described earlier, the call to start the process of callback (also know as trigger call) usually cost nothing to the customer. So, in 2001, by owning a mobile phone in some part of Africa could make you in some ways a small phone operator. Some people would sign up to the service as agents (getting a commission on all calls made by the customers they signed up). Their customers would come to them when they wanted to make a call and these agents would prepaid their accounts. Customers would then be able to use the agent’s phone to make calls to their relatives. Each of the customers would have a separate account in regard to the callback operator but they will all use the same “source” number, the mobile phone number of their agents. To prevent fraud, all the accounts are to be protected by a password so that a client cannnot use somebody else account to make calls.

This means that a same phone (usually a mobile one) could be used to make tens or hundreds of calls in one day. The advantage of the mobile phone was that the agent could travel with it and go see his customers rather than having to get them to come to a phone shop, especially in rural areas. In 2001, cell mobile phone penetration was still small and it meant 2 things:

  1. People could make a living by working as callback phone agents, owning one or more phones
  2. International calls to landline and mobile phones in most African countries would generally be priced the same

So, the callback system, initially designed to help make cheaper calls by increasing competition in countries with a monopolistic incumbent, became a way for hundreds of people to share one single phone (or a couple). Instead of linking accounts to the actual phone, customers’ accounts were linked to the number required to trigger the call.