“It works like this: you pay cash to your local agent – often at the nearest corner shop, if you live in a city – who then tops up your mobile money account using a secure form of SMS text messaging. That money can be transferred to another person by sending an SMS to their cellphone account. People without mobile money accounts can receive payments in the form of a text code which can be forwarded to their local agent, who exchanges it for cash.
The system relies on what is known as the unstructured supplementary service data (USSD) system that is built into the GSM cellphone network. It is USSD that allows pay-as-you-go customers to find out their credit balance, for example.”