Boxes and Dongles for Phones and Tablets: Basic Concepts
1. What is a box, and what is inside the box?
A box for phones is a device used to repair a phone having a software failure. It gets connected to a PC. In most cases, the device has a metal case; occasionally, the case can be made of plastic. Usually the box has the following connectors:
- USB - to connect to a PC;
- UART / Service - to connect devices via COM interface;
- USB hub - to connect other USB devices (e.g., flash drives), but not for phone servicing procedures;
- JTAG - to connect devices via JTAG interface.
Usually, there is a card reader for smart cards inside the box. A smart card serves as a protection against unauthorized use of software and, if necessary, can identify the client on the software developer’s server.
2. What is a dongle?
In fact, a dongle is a card reader for smart cards. It comes in a form factor similar to a common flash drive, with a simple USB connector. The only difference is that there is a smart card inside. There are no more interfaces, therefore, to service devices, only PC ports or ports of other boxes will be used. If you need to connect the phone via a COM port, you will have to use a built-in PC port. If you work with a laptop, a dongle will be most likely the least convenient solution, since modern laptops do not have built-in COM ports. However, exceptions still occur. Alternatively, you can use your another box, if available. If you are aimed to work with the JTAG interface, there is only one way out - to buy a specialized box, not a dongle.
3. How to connect the box correctly?
Having purchased a new box, you will usually find a box per se and a set of cables included in the package. All boxes are connected to a computer using a USB A-B cable. This is an ordinary cable, which an average person uses almost every day, for example, when connecting a scanner, printer or other office equipment.
Thus, this cable connects a box to the connector, usually marked as USB IN, and the other end of the cable is connected directly to the computer, to the USB port. Do not use USB hubs and extension cables to connect boxes. As a result the box can work incorrectly, or the computer may not be able to recognize the connected device at all. It is also not recommended to use USB 3.0 ports.
4. What is a smart card?
A smart card is used to authenticate your purchase and identify your device on the developer’s server. In fact, it looks like a regular SIM card, the same as the one for mobile phones. It has some memory, in which certain data are recorded: the firmware version, the card firmware itself, and other special information. It is important to remember that a smart card has a limited number of information recording cycles. Therefore, never try to perform the smart card update procedure without necessity. The card can simply be blocked and then, most likely, you will have to replace the smart card or the entire box (it all depends on the box developer). If you are not able to update a smart card, when asked for an update, it's best to contact technical support.
Always update the smart card firmware when the software requires. If there are no update requests, you should not do this, and your card will serve you longer.