GPRS

General packet radio service (GPRS) is a packet oriented mobile data service on the 2G and 3G cellular communication system's global system for mobile communications (GSM). GPRS was originally standardized 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 usage is typically charged based on volume of data. This contrasts with circuit switching data, which is typically billed per minute of connection time, regardless of whether or not the user transfers data during that period.
GPRS data is typically supplied either as part of a bundle (e.g., 5 GB per month for a fixed fee) or on a pay-as-you-use basis. Usage above the bundle cap is either charged per megabyte or disallowed. The pay-as-you-use charging is typically per megabyte of traffic.
GPRS is a best-effort service, implying variable throughput and latency that depend on the number of other users sharing the service concurrently, as opposed to circuit switching, where a certain quality of service (QoS) is guaranteed during the connection. In 2G systems, GPRS provides data rates of 56–114 kbit/second. 2G cellular technology combined with GPRS is sometimes described as 2.5G, that is, a technology between the second (2G) and third (3G) generations of mobile telephony. It provides moderate-speed data transfer, by using unused time division multiple access (TDMA) channels in, for example, the GSM system. GPRS is integrated into GSM Release 97 and newer releases.

WiFi Network

Wi-Fi is short for Wireless Fidelity, which has a standard set of terms that are used for Wireless Local Networks (Wireless Local Area Networks - WLAN) based on IEEE 802.11 specification. The latest standard specifications of 802.11a or b, such as 802.11 g, is currently in preparation, the new specification offers many improvements ranging from wide coverage farther up the transfer speed
Wi-Fi was originally intended for the use of wireless devices and Local Area Network (LAN), but now more widely used for accessing the internet. This allows anyone with a computer with a wireless card (wireless card) or personal digital assistant (PDA) to connect to the Internet using an access point (otherwise known as hotspots) nearby.
Wi-Fi is designed based on the IEEE 802.11 specification. Today there are four variations of the 802.11, namely:

    802.11a
    802.11b
    802.11g
    802.11n
In many parts of the world, the frequencies used by Wi-Fi, users are not required to obtain permission from local regulators (eg, the U.S. Federal Communications Commission). 802.11a uses a higher frequency and therefore its range is narrower, more equal.
Wi-Fi version of the most extensive in the U.S. market today (based in IEEE 802.11b / g) operates at 2400 MHz to 2483.50 MHz. With so allows operation in 11 channels (each 5 MHz), centered on the following frequencies:

    Channel 1 to 2.412 MHz;
    Channel 2 to 2.417 MHz;
    Channel 3 to 2.422 MHz;
    Channel 4 to 2.427 MHz;
    Channel 5 to 2.432 MHz;
    Channel 6 to 2.437 MHz;
    Channel 7 to 2.442 MHz;
    Channel 8 to 2.447 MHz;
    Channel 9 to 2.452 MHz;
    Channel 10 to 2.457 MHz;
    Channel 11 to 2.462 MHz
Technically operational, Wi-Fi is one variant of communications and information technology that works on the network and the WLAN (wireless local area network). In other words, Wi-Fi is a certification trademark given to telecommunications equipment manufacturers (internet) working on the WLAN network and interoperates capacity meets the required quality.
Internet technology-based Wi-Fi is built and developed a group of engineers who worked on the United States Institute of Electrical and Electronis Engineers (IEEE) technical standards-based devices numbered 802.11b, 802.11a and 802.16. Wi-Fi devices are not only able to work on WLAN networks, but also on the network Wireless Metropolitan Area Network (WMAN).
Due to the technical standard 802.11b WLAN devices intended for use at frequencies of 2.4 GHz or commonly called ISM (Industrial, Scientific and Medical). As for the technical standards 802.11a and 802.16 WMAN destined for the device or also called Wi-Max, who works in the frequency band 5 GHz.
High public interest, particularly among the community of Internet-using Wi-Fi technology because at least two factors. First, the ease of access. This means that users in one area can access the Internet simultaneously without the need to bothered with cables.
Consequently, users who want to surf or browse the news and information on the Internet, simply bringing the PDA (pocket digital assistance) or Wi-Fi enabled laptop into a place where there is an access point or hotspot.
The proliferation of hotspots in those places, which was built by telecom operators, Internet service providers, individuals and even triggered a second factor, namely because construction costs are relatively inexpensive or only around 300 dollars U.S..
Increasing the quantity of Internet users based on Wi-Fi technology is increasingly implicated in various parts of the world, has prompted Internet service providers (ISPs) to build hotspots in major cities of the world.
Some observers have even predicted in 2006, there will be about 800,000 hotspots in the countries of Europe, 530,000 in the United States and one million in the countries of Asia.
The overall amount of income derived by the United States and European countries of technology-based Internet business Wi-Fi by the end of 2003 was estimated at 5.4 trillion U.S. dollars, an increase of 33 billion U.S. dollars from the year 2002 (www.analysys.com).
Wi-fi hardware on the market currently exists in the form:

    PCI
    USB
    PCMCIA
    Compact Flash
There are 2 modes of Wi-Fi access, which is

    Ad-Hoc. This connection mode is a mode where multiple computers are connected directly, or better known as Peer-to-Peer. The advantage, cheaper and more practical when connected only 2 or 3 computers, without having to buy an access point
    Infrastructure. Using the Access Point that serves as a regulator of the data traffic, allowing many clients to connect over a network (network).
There are several types of security settings for Wi-Fi, among others:

    WPA Pre-Shared Key
    WPA RADIUS
    WPA2 Pre-Shared Key Mixed
    RADIUS WPA2 Mixed
    RADIUS
    WEP

Two kinds of modem

There are two kinds of modem :

1. Internal modem

    Internal modem is cheaper than external one but its installation is more difficult. Internal modem is a  modem device that is placed into a single unit with the motherboard on the system CPU unit. Internal modem can not be moved from one computer to another computer dirrectly (we must open the CPU casing).




      2. External modem
          External modem is easier in installation and can be moved from one computer to another easily (without opening the CPU casing), safe from lightning, but its price is more expensive.