CELLULAR ROUTER

A mobile broadband modem is a type of modem that allows a personal computer or a router to receive Internet access via a mobile broadband connection instead of using telephone or cable television lines. A mobile Internet user can connect using a wireless modem to a wireless Internet Service Provider (ISP) to get Internet access.
While some analog mobile phones provided a standard RJ11 telephone socket into which a normal landline modem could be plugged, this only provided slow dial-up connections, usually 2.4 kilobits per second (Kbit/s) or less. The next generation of phones, known as 2G (for 'second generation'), were digital and offered faster dial-up speeds of 9.6kbit/s or 14.4kbit/s without the need for a separate modem. A further evolution called HSCSD used multiple GSM channels (two or three in each direction) to support up to 43.2kbit/s. All of these technologies still required their users to have a dial-up ISP to connect to and provide the Internet access - it was not provided by the mobile phone network itself.

The release of 2.5G phones with support for packet data changed this. The 2.5G networks break both digital voice and data into small chunks, and mix both onto the network simultaneously in a process called packet switching. This allows the phone to have a voice connection and a data connection at the same time, rather than a single channel that has to be used for one or the other. The network can link the data connection into a company network, but for most users the connection is to the Internet. This allows web browsing on the phone, but a PC can also tap into this service if it connects to the phone. The PC needs to send a special telephone number to the phone to get access to the packet data connection. From the PC's viewpoint, the connection still looks like a normal PPP dial-up link, but it is all terminating on the phone, which then handles the exchange of data with the network. Speeds on 2.5G networks are usually in the 30–50kbit/s range.
3G networks have taken this approach to a higher level, using different underlying technology but the same principles. They routinely provide speeds over 300kbit/s. Due to the now increased internet speed; internet connection sharing via WLAN has become a workable reality. Devices which allow internet connection sharing or other types of routing on cellular networks are called also cellular routers.
Further evolution is the 3.5G technology HSDPA, which provides speeds of multiple Megabits per second. Several of the mobile network operators that provide 3G or faster wireless internet access offer plans and wireless modems that enable computers to connect to and access the internet. These wireless modems are typically in the form of a small USB based device or a small, portable mobile hotspot that acts as a Wi-Fi access point (hotspot) to enable multiple devices to connect to the internet. WiMAX based services that provide high-speed wireless internet access are available in some countries and also rely on wireless modems that connect to the provider's wireless network. Wireless USB modems are nicknamed as "dongles".
Early 3G mobile broadband modems used the PCMCIA or Express Card ports, commonly found on legacy laptops. The expression "connect card" (instead of connection card) had been registered and used the first time by Vodafone as a brand for its products but now is become a brandnomer or generalized trademark used in colloquial or commercial speech for a similar product, made by different manufacturers, too. Major producers are Huawei, Option N.V., and Novatel Wireless. More recently, the expression "connect card" is also used to identify internet USB keys. Vodafone brands this type of device as a Vodem.
Often a mobile network operator will supply a 'locked' modem or another wireless device that can only be used on their network. It is possible to use online unlocking services that will remove the 'lock' so the device accepts SIM cards from any network.
Standalone mobile broadband modems are designed to be connected directly to one computer. In the past, the PCMCIA and Express Card standards were used to connect to the computer. As USB connectivity became almost universal, these various standards were largely superseded by USB modems in the early 21st century. Some models have GPS support, providing geographical location information.

Many mobile broadband modems sold nowadays also have built-in routing capabilities. They provide traditional networking interfaces such as Ethernet, USB, and Wi-Fi. Models are available for both consumers and enterprises. Some require the use of an AC adapter, while others are portable and can also be powered by a USB connection or a built-in battery. An RJ11 registered jack is also present on a few of these modems, allowing the connection of a traditional home phone to make cellular calls.
Numerous smartphones support the Hayes command set and therefore can be used as a mobile broadband modem. Some mobile network operators charge a fee for this facility, is able to detect the tethering. Other networks have an allowance for full speed mobile broadband access, which—if exceeded—can result in overage charges or slower speeds.
An Internet-accessing Smartphone may have the same capabilities as a standalone modem, and, when connected via a USB cable to a computer, can serve as a modem for the computer. Smartphone’s with built-in Wi-Fi also typically provide routing and wireless access point facilities. This method of connecting is commonly referred to as "tethering."

General Packet Radio Service (GPRS) is a packet oriented mobile data standard on the 2G and 3G cellular communication network's global system for mobile communications (GSM). GPRS was established by European Telecommunications Standards Institute (ETSI) in response to the earlier CDPD and i-mode packet-switched cellular technologies. It is now maintained by the 3rd Generation Partnership Project (3GPP).

GPRS is typically sold according to the total volume of data transferred during the billing cycle, in contrast with circuit switched data, which is usually billed per minute of connection time, or sometimes by one-third minute increments. Usage above the GPRS bundled data cap may be charged per MB of data, speed limited, or disallowed.