Twin card
As Twin card (often the English term is TwinCard used) is a duplicate of a card SIM referred. Both cards therefore have the same telephone number .
The most common purpose is to use at least two cell phones without having to change the SIM card each time. Whether only one phone can be ready to receive at a time, or both or even several, depends on the provider and the technology used.
This is an additional service that is offered by a few mobile phone providers .
The opposite purpose of using two telephone numbers with just one cell phone can be implemented in four ways:
- Dual SIM adapter (does not fit into every cell phone)
- Dual SIM cell phone (many attractive cell phone models are not offered as dual SIM cell phones).
- Special SIM card such as DuoBill or TwinBill , with which you decide via a six-digit PIN (instead of four-digit) which phone number (and therefore billing) you want to use to log in. In most cases, a new telephone call can then be billed to the other number using the star preselection key .
- Alternate Line Service (ALS) (a pure software solution).