There are several tactics to use multiple phone numbers. Four notable solutions are listed here â€“ please keep in mind that at the time of this research (2007), there was only very few mobile phone models that had the dual SIM feature.
Solution 1. Carrying two or more SIM cards but only one mobile
Not everyone can afford to buy multiple phones, or wants to carry two mobile phones with them all the time. The extra SIM card is carried in a safe place such as inside wallet or inside the battery cover of the phone, which makes an intuitive storage for switching the cards. Some people who go for this solution are typically well aware of call divert function as it allows receiving calls from both numbers even though there is only one active number to make calls at a time.
Solution 2. Multiple phones â€“ A phone per number
In markets where users do not have separate SIM cards, this is the only solution for the user to get multiple phone numbers â€“ while in GSM markets it is a matter of usersâ€™ preference and affordability. Users may maintain separate phone book on each of the phones â€“ sometimes intentionally (refer to 1. lowering the cost of communication), sometimes because they do not have the option of easily synchronize them. When affordability is not an issue, physically separating the phone per number provides the greater control over managing the multiple points of contacts.
Solution 3. Mobile phone with multiple SIM card slots
At the time of research, there were very few multiple SIM phones in the market from the known brands. However we observed a few Shanzai phones featuring dual SIM. Obviously after 4 years, this feature has become a de facto requirement for a mobile phone. There are numerous new mobile phone brands popping up in India, and invariably all their products feature dual SIM, sometimes triple SIM functionality.
Solution 4. Stitching up multiple SIM cards into one
We found a service offered by a local mobile phone dealer (Mobile Phone People, one of the Nokia authorized dealers) in Ghana. It costs 15 euros to have the two SIM cards combined into one. There is an even more advanced operation, which requires a special SIM card imported from Finland. This card can host up to 16 SIM cards into one, but costs 40 euroes. Either of these operations costs considerably high for the market, as it is more than purchasing a mobile phone. Therefore the clientele is mostly business people who do need to have two or more numbers but do not want to go through the inconvenience of switching SIM cards or carrying multiple phones.
Interviewing the engineer who was working at this service center mentioned that this technology is from Finland, but cannot tell more about its source as it is a business secret. He was proud to say that he was the first one who got trained for this operation in Ghana, and subsequently he trained others working currently in the shop. The way this operation worked was brilliant at the short sight, but obviously I suspect that it may have the legal issues in terms of manipulating the network SIM card directly. 4 years down the road, I donâ€™t see this service booming in the market.
I havenâ€™t had a chance yet to study how people actually manage multiple phone numbers â€“ the multiple identities on their dual SIM phones. If the mobile usage goes beyond the voice calls, it will definitely require design considerations in various parts of the mobile phone applications, as it no longer is going to be an issue of cost management, but identity management. Technologically and as a matter of market availability, owning multiple mobile phone numbers is now very easy. But its potential and implications is largely unexplored beyond the manufacturing of physical hardware.