Useful Information
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Bulgarian cell phone frequency/ Bulgarian GSM frequencies
There are two frequency bands in Bulgaria - 900 MHz and 1800 MHz. In order to use our Intra Smart SIM rental package, you need an unlocked GSM cell phone, working either on 900 MHz or on 1800 MHz frequency band. Our Intra Smart SIM Package offers you the opportunity to receive FREE incoming calls, make local and international calls at low rates, and all this with absolutely no obligation to annual contracts nor prepaid vouchers! You can hire your pre-activated SIM card for only 5 €/ week.
Bulgarian cell phone providers/ Bulgarian GSM providers
There are now three mobile phone operators - MTel, Globul and Vivatel, and one GSM cell phone rental provider - Intrafonica Bulgaria, also offering mobile internet delivered via GPRS, and SIM cards for hire so you can avoid inflated roaming rates and paying for being called.
GSM
GSM (Global System for Mobile Communications) is the world's leading cell phone standard, which was first adopted in Europe and then spread throughout Asia, Africa and the Pacific. That is why the same cell phone that works in London also works in Johannesburg, Beijing and Sydney. The United States, however, did not adopt this standard and let the competitors create different standards for their own networks, which are incompatible with the one, operating on different frequencies. Consequently a typical US cell phone will not work overseas.
The Advantages
GSM is a digital technology. Besides its ubiquity, which provides significant advantage over other less common digital technologies, its main advantages compared to the analog are:
- Excellent sound quality
- High level of communication security
- International roaming (every GSM subscriber can make and receive calls, while abroad, provided he had activated the roaming function of his cell phone)
- Advanced services such as fax and data transfers
- Automatic tuning to the right frequency
Different frequencies
Europe, Africa, Asia, and the Pacific countries adopted the GSM standard, according to which the GSM cell phone networks would operate on the same frequency: the 900 MHz, initially and later - the 1800 MHz band. Thus a GSM cell phone network, operating overseas, will offer service on the 900 and/or the 1800 frequency. Some cellular carriers will offer service on both bands and having a GSM cell phone that includes both of these frequencies can improve the overall quality of service and coverage. A GSM 900/1800 compatible cell phone is an international cell phone capable of operating in over 140 countries spread over 4 continents.
North American GSM providers operate on 1900 frequency only. Consequently if you have a GSM cell phone in the United States or Canada, in most cases it is a GSM 1900 MHz ONLY. So if you happen to be one of the few subscribers with a GSM cell phone in the US, you are still most likely to be out of luck when it comes to using your cell phone overseas.
There are parts of the world, where the GSM technology is very new or is still not implemented at all, and coverage may vary significantly. For guaranteed coverage, the use of a Satellite phone is recommended.
GSM coverage in Bulgaria
In Bulgaria, as in most of Europe, the GSM coverage is 80-90%, i.e. you will have coverage in almost all parts of the county and virtually you will need no satellite phone. Anywhere you have coverage, you can make and receive local and international calls. The quality of the signal depends on several factors like the landscape, the location and the density of the buildings, the mobile phone features and specifications, etc. These factors exert influence on the connection quality, but still they do not interfere the casual wireless communication.
Hybrids
Some cell phones are “hybrid phones”, which means that they operate on two different standards. Also there are the so called “world phones”, which operate on 2 or 3 frequency bands like GSM 900/ 1800/ 1900 or GSM 900/ 1900.
The Nextel i2000 is an example of a hybrid phone that operates on I-den, in the United States and GSM 900, when overseas. The Siemens S46 made for AT&T is an example of a hybrid phone that operates on TDMA, GSM 900, 1800 and 1900. The TDMA provides NO advantage overseas and is strictly for AT&T customers in the United States.
All this comes to say that now-a-days technology offers us no single cell phone with global coverage, except for the satellite phones, which work as long as they can see the sky, but won't work indoors. That is why resorting to the services of a cell phone rental company, would be the most efficient and cost effective way to go.
SIM cards
GSM cell phones cannot work on their own. The user has to activate his/ her phone by inserting a tiny smart chip, called SIM card (Subscriber Identification Module), which allows him/ her to make and receive calls. The embedded circuitry located on the SIM card stores information about the services that are available to you as a local subscriber. The SIM card identifies you to the network and contains a microprocessor chip, which stores unique information referring to your account. It is the SIM card that determines your telephone number and NOT your cell phone. Therefore, every time you change your SIM card, you are getting a new telephone number and a new, although not always different, array of GSM services (caller ID, fax, data, call divert, voicemail, etc).
In general, SIM cards are available either on a subscription basis, in which case you have to sign a contract and get a bill every month, or on a prepaid basis, in which case you buy airtime in advance, but it costs more.
Locked and unlocked GSM cell phone
A locked cell phone is one that has been altered in order to use only one particular cellular network. This is often referred to as a service provider lock or "SP lock" for short. All GSM network operators lock the GSM cell phones they sell or offer with their cellular services. This is the hidden cost of the otherwise "free" or heavily-discounted phone you might receive directly from a network operator by signing a service contract. An unlocked phone is therefore one where this software restriction has been removed. So how can you check if your cell phone is locked? You can either contact your GSM operator, or you may try to swap your SIM card and see if it works. If it doesn’t – go for our Intra Rental Package!
Europe-compatible GSM
GSM is implemented on different frequencies across the planet: Europe, Asia and Africa including the South Pacific operate on 900 MHz and 1800 MHz; North America and Central America operate on the 1900 MHz; South America and The Caribbean may use the 900Mhz, 1800Mhz and/or the 1900 MHz frequencies; The United States, Canada and Panama have added the 850 frequency.
Available GSM Services
Your GSM phone can provide you with a wide range of services. They vary depending on the network provider and the specifications of the cell phone. Listed below are just some of the typical services.
Call Waiting
If you receive a call, while talking, instead of giving the "busy" signal, the Call Waiting option will alert you that you have a second caller, thus enabling you to put him/her on hold, receive or reject the call.
Call Hold
Use Call Hold to put the person you are talking to "on hold" so you can call another party, and then switch between the two calls.
Call Forwarding
Use Call forwarding to divert incoming calls to another number.
Calling Line Identification Presentation (CLIP)
The CLIP service enables you to see the number or the name of the person (if stored on your phone), making the incoming call.
Closed Group
Closed group is a group of 2 or more accounts providing lower fares on calls among the members of the group.
SMS (short messaging service)
SMS allows you to send & receive text messages to and from your mobile phone. The text can comprise of words or numbers or an alphanumeric combination. This services is provided by most of the world's GSM networks. In addition to the simple user-generated text messages, most providers include services like news, sports, financial, language and location based services, mobile banking facilities and leisure booking services.
Each short message is up to 160 characters is length when Latin alphabets are used, and 70 characters in length when non-Latin alphabets such as Arabic and Chinese are used.
Data Services
Using your GSM phone to receive and send data is the essential building block leading to widespread mobile Internet access and mobile data transfer. GSM currently has a data transfer rate of 9.6 kb. New developments that will push up data transfer rates for GSM users are HSCSD (high speed circuit switched data) and GPRS (general packet radio service). And best of all there is Bluetooth to make connecting your GSM cell phone to your PDA or laptop, as easy as setting them together down on a table top.
HCSD
High Speed Circuit Switched Data (HSCSD) is an enhancement of data services ("Circuit Switched Data - CSD) of all current GSM networks. It allows you to access data services at 3 times faster, which means subscribers are able to send and receive data from their portable computers at a speed of up to 28.8 kbps; this is currently being upgraded in many networks to rates of and up to 43.2 kbps.
The HSCSD solution enables higher rates by using multiple channels, allowing subscribers to enjoy faster rates for their Internet, e-mail, calendar and file transfer services.
HSCSD allows you to access your company LAN, send and receive e-mails, access the internet whilst on the move. HSCSD is currently available to 90 millions subscribers across 25 countries around the world and with the implementation of International Roaming agreements between all HSCSD Operators life on the move just got easier.
GPRS
General Packet Radio Service (GPRS) enabled networks offer 'always-on', higher capacity, Internet-based content and packet-based data services. This enables services such as color Internet browsing, e-mail on the move, powerful visual communications, multimedia messages and location-based services.
Bluetooth
Bluetooth is the key to enabling wireless personal area networks (WPAN) that connect devices in close proximity or short range radio devices. Bluetooth encompasses both a standard communications interface and a low-cost computer chip. Bluetooth as a technology was conceived by Ericsson in 1994 and in 1998 the Bluetooth SIG trade association was founded by Nokia, Ericsson, IBM, Intel and Toshiba.
Bluetooth operates in the globally available 2.45 GHz ISM 'free band' and provides low-cost, low power, robust, secure, efficient, high capacity, ad hoc voice and data networking of up to 1 Mb/sec, in a range of 10 meters. Unlike IRDA it does not require line of sight allowing devices to communicate with each other from pockets, bags and around corners.
Products available today that support Bluetooth include: Access Points, cable replacement, cordless phones, embedded devices, PDAs, headset, mobile phones, modems, PC Cards, portable PCs, printers, USB Devices and car kits.
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