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The name Datalinx quickly defines our focus. "Data" refers to information, "Linx" refers to linking one point to another. Datalinx transmits information (about the customer's retail sale transaction or purchase) from one point to another to reach its final destination, the bank.
Datalinx's communications device is called CellPAD - "Cell" refers to Cellular frequencies, and "PAD" stands for Packet Assembler and Dissembler.
CellPAD is a GPRS Communications Industry device, used to support financial transaction switching services.
For example, companies like PRISM EasyPay switch Cheque Guarantee Services (CGS) and Vision transactions from Retail POS systems to the relevant back-end system such as CellPAD which provides the processing support.
EFT (Electronic Funds Transfer) may be initiated by a cardholder when a payment card such as a credit card or debit card is used. This may take place at an ATM or point of sale (POS). The customer's card is swiped through a card reader or inserted into a chip reader and the merchant usually enters the amount of the transaction before the customer enters her/his PIN.
Simply put, the CellPAD itself sends financial transaction data or payment information from the Retailer’s shop (the EFTPOS Terminal contacts the server via the CellPAD) to the bank’s computer, and then from the bank back to the shop (to CellPAD, to the EFTPOS Terminal) again, until the transaction goes through.
GPRS is a product of the GSM networks and therefore Datalinx relies entirely on the cellular networks’ base stations to operate wireless data transfer services to our clients.
Let’s look at this technology and the context of how it evolved more closely.
1. History of financial data transfer services in SA
Older technologies
Dial-up
Before GPRS, for many decades the telephone line has had to be used as means of data communication, and customers were subject to a monopoly in terms of service provider. This method, usually referred to as Dial-up, is costly and slow.
Datalinx identified the opportunity to improve this, and introduced the CellPad. CellPAD uses GPRS, which lowers costs and increases transaction processing speeds, to wirelessly transfer secure data, replacing dial-up.
Radio-based
Another method of data transfer was “Radio-based”. This method relies on the number of Radio base-stations installed in various areas of the country. A company providing radio-based data transfer must install its own costly base station infrastructure.
However, most radio base-stations were only installed in some major city centres. There are many regions of South Africa where radio base-stations could not be installed, which means that the retail outlets were limited to cash-only transactions or to using the costly dial-up method.
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Revolutionary Technology
2003 - GPRS-based financial data transfer innovated by Datalinx Technologies
Datalinx Technologies pioneered this use of this new technology as communications for financial transaction processing, via our CellPAD. Along with Network Service Provider MTN-NS, we defined the road maps for other companies to follow.
GPRS-based wireless data transfer uses the cellphone giants’ infrastructure of GPRS base stations. MTN & Vodacom cover 95% of South Africa.
Using GPRS allows Packet Switching
GPRS is packet-based. Computer communications links that do not support packets, such as traditional point-to-point telecommunications links, simply transmit data as a series of bytes, characters, or bits alone. When data is formatted into a packet, the network can transmit longer messages more efficiently and reliably. Users of GPRS benefit from shorter access times and higher data rates (more information transmitted at one time).
Packet-switched services offer massive cost-savings, as billing can be based on the amount of transmitted data only. The client now can be "online" over a long period of time but will be billed based on the transmitted data volume and not the time. In circuit-switched services, billing was based on the duration of the connection. This is unsuitable for applications with bursty traffic. The user had to pay for the entire phone-time, even for idle periods when no packets are sent (e.g. when the user read a Web page).
So GPRS packet transmission offers a far more competitive billing than circuit-switched services such as the telephone line (dial-up method) because GPRS does away with telephone charges by minute, where you paid for waiting.
How are data packets transmitted?
The GPRS Core Network is an overlay architecture on the GSM core network, to provide packet-switched data services and support for third-generation 3G networks. The services associated with 3G provide the ability to transfer voice data and non-voice data such as downloading information, exchanging email and instant messaging. The GSM network is divided into three major systems: the switching system (SS), the base station system (BSS), and the operation support system (OSS). The GPRS system is used by GSM Mobile SIM cards for transmitting IP Packets.
The key element of GPRS is that it uses packet-switched data transmission technology rather than circuit-switched data, and this technique is optimized for bursty traffic such as Internet/intranet services so it makes much more efficient use of the available capacity. This is because most data transfer occurs in what is often termed a "bursty" fashion. The transfer occurs in short peaks, followed by breaks when there is little or no activity. Using a traditional approach a circuit is switched permanently to a particular user. This is known as a circuit switched mode. In view of the bursty nature of data transfer it means that there are periods when it will not be carrying data.
The General Packet Radio Service (GPRS) is a mobile data service available to users of GSM mobile phones or SIM cards, that greatly improves and simplifies wireless access to packet data networks, e.g. to the Internet.
GPRS is packet-switched, which means that multiple users share the same transmission channel, only transmitting when they have data to send. This means that the total available bandwidth can be immediately dedicated to those users who are actually sending at any given moment, providing higher utilisation where users only send or receive data intermittently. Packet-switched data under GPRS is achieved by allocating unused cell bandwidth to transmit data. One of the main benefits for users is that they can always be online and may be charged for service based on the amount of transmitted data.
To achieve this the data is split into packets and tags inserted into the packet to provide the destination address. Packets from several sources can then be transmitted over the link. As it is unlikely that the data burst for different users will occur all at the same time, by sharing the overall resource in this fashion, the channel, or combined channels can be used far more efficiently. This approach is known as packet switching.
Data transfer using GPRS is faster because of the technology used and the extensive network coverage available. In order to set up a GPRS connection for a wireless modem, Datalinx Technologies specifies an Access Point Name (APN) and IP address, which are provided by network operator MTN-NS.
An IP address can be thought of as the equivalent of a street address or a phone number for a computer or other network device on the internet. Just as each street address and phone number uniquely identifies a building or telephone, an IP address can uniquely identify a specific computer or other network device on a network. Any participating Internet Protocol (IP) network device — including routers, computers, time-servers, printers, Internet fax machines, and some telephones — must have its own unique address.
When TCP/IP is used, each SIM card can have one or more IP addresses allocated.
- TCP/IP protocol suite is named after the two most important protocols in the Internet Protocol (IP) suite: Transmission Control Protocol (TCP) & Internet Protocol (IP).
- The Internet Protocol (IP) is the set of data-oriented or communications protocols, used for communicating data across a packet-switched internetwork. These communications protocols implement the protocol stack on which the Internet and most commercial networks run. IP is a network layer protocol in the internet protocol suite and is encapsulated in a data link layer protocol (e.g. Ethernet).
The most complex aspects of IP are IP addressing and routing.
- Addressing refers to how end hosts become assigned IP addresses and how subnetworks of IP host addresses are divided and grouped together.
- IP Routing is performed by all hosts, but most importantly by internetwork routers. Routing occurs at layer 3 (the Network layer e.g. IP) of the OSI seven layer protocol stack.
GPRS will store and forward the IP packets to the SIM card (inside the Datalinx CellPAD) during cell handover - when it moves from one cell to another, going from tower to tower. In this way data can be quickly sent over vast geographical regions.
So, by using CellPad, Retailers can expand their businesses into farther geographical areas, enabling them to realise opportunities to increase revenues and national footprint, whilst providing a service to remote communities.
GPRS enables several new applications: Internet applications, from web browsing to chat; location-based applications or e-commerce over the mobile network. Other new applications for GPRS include file transfer and remote monitoring/control of house appliances or mission-critical machines.
GPRS allows improved quality of data services as measured in terms of reliability, response time, and features supported.
CellPAD has improved the spending power of the consumer, because major retailers opened outlets in places or areas where they weren’t able to before.
2. Looking into the Future
Current industry trends
New industry standards recently beginning to appear in South Africa:
EDGE
Enhanced Data rates for GSM Evolution (EDGE), also known as EGPRS, is a digital radio-based high-speed mobile data standard which acts acts as a bolt-on enhancement to 2G and 2.5G General Packet Radio Service (GPRS) networks.
EDGE provides Enhanced GPRS (EGPRS), which can be used for any packet-switched application such as an Internet connection. High-speed data applications such as video services and other multimedia benefit from EGPRS' increased data capacity. EDGE provides three times the data capacity of GPRS, because it is a technology that gives GSM the capacity to handle services for 3G, the third generation of mobile telephony.
Using EDGE, operators can handle three times more subscribers than GPRS; triple their data rate per subscriber, or add extra capacity to their voice communications.
EDGE can function on any network with GPRS deployed on it, provided the carrier implements the necessary upgrades. EDGE uses the same TDMA frame structure, logic channel and 200kHz carrier bandwidth as today's GSM networks, which allow existing cell plans to remain intact.
The maximum data rates are achieved only by allocation of more than one time slot in the TDMA frame. Also, the higher the data rate, the lower the error correction capability. Generally, the connection speed drops logarithmically with distance from the base station.
3G
GPRS is important as a migration step toward third-generation (3G) networks. GPRS will allow network operators to implement an IP-based core architecture for data applications, which will continue to be used and expanded upon for 3G services for integrated voice and data applications.
In addition, GPRS will prove a testing and development area for new services and applications, which will also be used in the development of 3G services.
HSDPA
High-Speed Downlink Packet Access (HSDPA) is a new mobile telephony protocol sometimes referred to as a 3.5G (or "3½G") technology and extends WCDMA.
HSDPA will make life easy for 3G customers, providing vastly better service for both corporate users and individuals, with data delivered at speeds comparable to, or better than, fixed-line broadband access systems.
- Corporate users will have easy and secure mobile access to corporate networks, with rapid retrieval and downloading of confidential corporate information.
- Consumers will enjoy superior quality for video services, including video streaming and gaming.
- All customers will enjoy fast Web browsing, with rapid access to graphics-heavy Internet sites.
Both MTN and Vodacom, two of South Africa's leading GSM operators, have already announced their deployment of the fast HSDPA service delivering theoretical downlink speeds of 1.8 Mbit/s after introducing UMTS 3G services more than 14 months ago. Vodacom was the first to deploy HSDPA commercially in South Africa, becoming the 14th network world-wide to deploy HSDPA.
HSDPA provides a smooth evolutionary path for UMTS networks, allowing for higher data capacity (up to 14.4 Mbit/s per cell in the downlink and 2 Mbit/s in the uplink per cell). It is an evolution of the W-CDMA standard, designed to increase the available data rate by a factor of 5 or more.
Future trends
In the future the Wireless Telecomms Industry is headed for:
WiFi
WiFi is the short form for Wireless Fidelity. It is IEEE 802.11 based suite of standards for Wireless Local Area Networks (WLAN).
In the corporate enterprise, wireless LANs are usually implemented as the final link between the existing wired network and a group of client computers, giving these users wireless access to the full resources and services of the corporate network across a building or campus setting.
WiFi allows LANs to be deployed without cabling, potentially reducing the costs of network deployment and expansion. Spaces where cables cannot be run, such as outdoor areas and historical buildings, can host wireless LANs.
Unlike packet radio systems, Wi-Fi uses unlicensed radio spectrum and does not require regulatory approval for individual deployers. Wi-Fi is a global set of standards. Unlike cellular carriers, the same Wi-Fi client works in different countries around the world.
Technology resources of interest:
www.wikipedia.com
http://www.telecomspace.com/index.html
http://www.radio-electronics.com/
http://www.prism.co.za/transaction-services.htm
www.mtn-ns.co.za
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