Utility of Modern Cell Phones

One can make a huge amount of savings by purchasing wholesale cell phones in the market. The purpose of buying these phones can vary. However, the ultimate aim is to get quality and affordable phones. In recent times, you are exposed to a great range of phones in the market. Hence it creates confusion while buying the phone models as every model is very elegant and exquisite. The cell phones are available in two models that include smart phones and the single-function phones.

A lot of people are resorting to the purchase of smart phones that have a lot of additional features. However, there are certain people who want to have the phones of old style. These phones were manufactured earlier and have less numbers of functionalities. The simplest function is that a person can make an outgoing call and receive an incoming call. You can also get the options of the internet browsing, text messaging and online music by the utilization of smart phones. These smart phones have got the functionalities of a reminder, notifications, daily planner and many other activities. Smart phone comes in the form of a pocket computer and helps you to increase your efficiency even at the time of being away from office.

It is possible for you to carry out your assignments sitting in any part of the world with most of the features available in the latest cell phones. Mobile phones also assist you during emergencies and one can also let the others know about the alterations and frequent updates made by him. It is important to check for the quality of the wholesale cell phones and the carrier interoperability. The technology can be either GSM or CDMA. An important factor is that, these cell phones must have the facilities to support the 3G system. It is a smart idea to buy quad-band cellular phones for the purpose of interoperability on the international level.

Installation of a Cell Extender

There are many names for an indoor cell extender. Commonly it is referred to as Cell Booster but in actual fact it is a fully functional low powered cellphone repeater. The industry refers to it as a mini, a pico or a SOHO repeater or a cell extender. There are indoor and outdoor types. There are different formats like CDMA, GSM, DSC, UMTS There are also combinations of the mentioned frequency formats and they are referred to as dual & even tri-band repeaters. All repeaters should be considered as the network operator's responsibility. The network and the frequency spectrum is their licensed property over which they supply specific services and for which the end user pays revenue. The quality of equipment used on these networks is their responsibility as well as to provide coverage through. Installations of any kind should be transported out by a fully qualified network technician or an appointed contractor.

Should a residence or business not have indoor cellphone coverage, their preferred network operator whose services have been assigned to be referred to prior to making such a decision? Only if this service is not forthcoming due to whatever reason, should a resident consider installation of an indoor cell extender.

• It must be remembered that this devise is an indoor repeater and has been designed to provide signal coverage indoors.
• Coverage within homes, lodges, storerooms, workshops, factories, shoppingalls, basements, offices, tunnels, all fall under the category of indoor coverage.
• These systems are not for repeating signal over any distances outdoors, but with use of multiple antennas and line amplifiers, large indoor or secluded arias can enjoy converge.
• Even though it is an indoor device it still needs to be installed by a qualified installer.
• Even though cell boosters are obtainable over the counter as a DIY kit it is austerely advised that you do not purchase one and try to install it yourself.

Before a cell extender is installed, have the RSSI (Received Signal Strength Indication) measured. This is done by a trained installer measuring the RSSI using a portable mast, high quality cable and antenna. This is achieved and the measurement is done using a portable spectrum analyzer, a portable signal strength meter or software used on a lap top or cell phone. Full signal may be indicated on your mobile, but no coverage is available from the network you need to connect with, so also determining which operators' signal is being measured is also relevant.

The RSSI is vendor dependent – in other words, the network being connected to can fluctuate, it can improve of deteriorate. BTS output power levels can be changed or an antenna can be turned a little into another direction, the network could intercept another BTS (Base Transmitting Station) or cellphone tower in the vicinity. A building or a bridge could have been built in between the BTS and the home or business shielding it totally. Because high frequencies are LOS (Line of Sight) dependent, these factors can change and individuals can be affected drastically. All these factors should be measured and recorded.

The RSSI measurement should be done at a height of not less than 7 meters from the ground. This is the minimum installation height of an outdoor antenna on a cell extender. Ground level RSSI is irrelevant for this purpose. It is imperative that you do have some signal on the site of installation – if there is no signal there is nothing to amplify. But, no signal at ground level does not mean there is no signal, there could be good signal just above the tree line.

What must be achieved? These measurements are curtail in determining what the outdoor (donate or up / link) gain should be. How many BTS towers in the coverage aria and their situation is information needed in selecting the correct antenna type to communicate between the BTS and the repeater. This criteria is not catered for in DIY kits. Antenna types, their radiation patterns and their strength (Gain) are not common knowledge to the layman. Once this is established, a link budget calculation can be calculated and the correct cell extender recommended. This will ensure a cell extender that does what it is designed to do and that is to give you indoor coverage. Incorrect calculation and unqualified installation will very likely lead to a system that oscillates, creates noise on the network and gives very limited coverage.

Typical signal strength evaluation One bar signal on you cell phone can be amplified to full strength with a cell extender. Signal strength is measure in dBm. Here is a rough guideline that could assist. Remember, this is what the user is experiencing at ground level. He may have full signal on a hill 100 meters from home.

5 Bar = -40-80 dBm very good
4 Bar = -85 dBm good
3 Bar = -90 dBm usable
2 Bar = -95 dBm may break up and drop calls
1 Bar = -100dBm poor

Theoretically using a Coiler TG900 27dBm cell extender with 60dB gain and selected antennas a site with -90dBm can be amplified to -27dBm which will provide coverage to a normal sized home. Between 7 ~ 10met radius on the GSM900 frequency is common. Much larger coverage arias have been achieved regularly but one designs to be very careful in sketching coverage when RF is being applied as it is not very predictable and so many variations apply.

Is it usable signal? There are weak signals, poor quality signals, noisy signals, reflected signals etc. The parable applies "garbage in, amplified garbage out". The better the RSSI before amplification, the better the coverage and the quality of the amplified signal. By reflected signal we mean the signal is bounced off a stationary object such as a mountain cliff or a building such as a silo etc. These signals are not always stable. Often this signal is varying in strength. Reflected signal can be amplified, but the repeater will not need to destabilize the violating signal.

Which Network Operator's signal is being amplified? Network Operators in SA often use the same infrastructure but many rural high sites host only one operators BTS. It is necessary therefore to ensure that the relevant base station provides the operator's service subscribed to. The broadband GSM repeater amplifies the whole GSM900 frequency spectrum and the other operator's signal is also amplified. This can mean that the user could have excellent operator 2 signal but weak operator 1 signal. The Service Providers / Network Operators use band selective transmitters and receivers (BTS) to control their own customer's billing and added services. This means only that operator's dedicated channels in the frequency spectrum will be enhanced and not their oppositions. This also assists them in identifying who is responsible when a problem arises.

Which services are amplified? By services we refer to:

• GSM900 (Global System for Mobile Communications) – voice, GPRS and 2G (2nd Generation) in SA
• GSM1800 or DCS (Digital Cellular Service) used for EDGE (Enhanced Data rates for Global Evolution) – Data and high density arias for voice in SA
• UMTS2200 (Universal Mobile Telecommunications System) commonly uses W-CDMA (Wideband Code Division Multiple Access), for 3G (3rd Generation) or HSDPA (High-Speed ​​Downlink Packet Access)

Because each of these technologies is being run on a specific frequency band, a repeater for that bandwidth or combination repeater engineered for two or more bandwidths is needed to enhance each format. GSM900 on the 900MHz frequency, DCS on the 1800MHz and UMTS on the 2.1GHz frequency. South Africa operates a Tri-Band network in its major suburban areas where all three services are available. In rural and minor suburb arias a dualband (GSM900 & DCS) or a singleband GSM900 & GPRS network should be available. The UMTS cell extender can not amplify 3G if the local BTS is not a UMTS carrier even if the end user's mobile is 3G enabled. He will have to be satisfied with GPRS or Edge.

Why is all signal not available in all arias? No network available. A network is rolled out according to a network plan. Services for arias are planned for and provided according to the potential market. The network operator is a business with shareholders all demanding the best dividends on their investments. A BTS to provide these services to the end user will not be authenticated for one or two farmers with the potential to generate R6000pm calls / sms's made by themselves and their workers. Where there is substantial inhabitancy of an aria a market for network services is created and accordingly coverage will be provided.

No coverage even though network is available due to distance. Approximate distance a frequency travels when generated at prescribed power level. (DBm power ratio in decibels) What is not commonly understood is that different frequencies have different wave lengths and are transmitted at different power levels as determined by the governing broadcasting body. The power level is determined due to the danger of Radio Frequency Radiation (RF) hazards. 1800MHz is already a low microwave frequency and 2.1 GHz is close to the 2.4GHz frequency most microwaves ovens operate on. Should this frequency be amplified indiscriminately, a real health hazard will be inevitable. Should you fall outside this radius you will experience weak signal.

No coverage even though network is available due to obstacles.
• A second point not commonly known is that the higher the frequency (the narrower the wave length) the more difficult it's penetration of obstacles, like trees, buildings, steel structures like roofs and hills etc.
A suck of the thumb indication over an obstacle-free field (LOS or line of site)
• GSM900 (900MHz) transmitted from a BTS should give a coverage distance / radius of 16km
• DCS1800 (1800MHz) transmitted from a BTS should give a coverage distance / radius of 7km
• UMTS (2200MHz) transmitted from a BTS should give a coverage distance / radius of 3km

3G and HSDPA have a lot of challenges in the cities centers due to penetration. Eg Accompany could have great 3G connectivity – then a bridge, a building or the Gautrain overhead rail is built across the up-town suburb between the BTS and your point of reception, and that is the end of the 3G signal. One only needs to move offices down the hall to lose a 3G signal and this is due to the penetration phenomena.

What should become clear is that it is no easy task giving coverage to every person in a diverse country such as South Africa. It is even more of a challenge to provide all the service available with cellphone technology coming up with new formats and medias such as "push technology" and video conferencing. It is not only about the phone but about the signal.

If need assistance, do not talk to just anyone. Talk to the right people.

Key Telephone Systems Vs VoIP-IP PBX Phone Systems

What is the difference between a Key Telephone System & a PBX Phone System? With the introduction of VoIP or IP Phone Systems, this old-technology question is becoming all the more relevant in your final decision to purchase the right phone system today.

I have cut and pasted the following text from a Google search, just to show you a classic example of a technically correct explanation for this question that would not only be technical jargon to you, but also throw up a bunch of new questions.

A key system has telephones with multiple buttons that permit the user to directly select the telephone company’s central office phone lines. A key telephone system (KTS) is not a switch.

A private branch exchange (PBX) allows several trunks (outside lines) from the central office to be shared and the switching for selecting these lines is within the PBX. A PBX is sometimes referred to as a phone switch.

Key systems are usually found in small companies where few features are required. A PBX is usually found in larger companies that need more capabilities.

Was I right?


– What is a switch? What is central office?- I didn’t quite understand why PBX is a phone switch and the KTS is not a switch?

– Why do I care? All I want is one phone on my desk for all my lines.

– It is great to get lots of features, but I still don’t know what I need and what I don’t.

– I am a small business, so do I have to look out for a Key Telephone System?

– Is the PBX Phone system not for me?

– Is the PBX more expensive?

– Well I don”t want to be stuck with something that is having few features, so what do I do?

– What are the features that a Key Telephone System has and the PBX doesn’t?

– I do know somebody who has a business phone system and he says its a PBX… he has a staff of six!! And I am confused! Did he get cheated? or Did he pay too much for something he didn’t need?

– Gosh, I can understand that there are different makes and models, but now I have to deal with different architectures in phone systems?

– Help!

Ok. Here is our version of the explanation…

And this is really the most important thing you will ever need to know in today’s market, where there are hundreds of new phone systems with VoIP technology, IP PBX Systems, IP Phone Systems that are competing with the Panasonic, Nortel, Avaya, NEC, Samsung types.

Just recently during a sales meeting, a prospective client was all in favour of the new VoIP PBX, but it was this KEY difference, (no pun intended!) that made them reject the VoIP PBX and choose the Traditional Key Telephone System from a well established manufacturer.

What was this “key “difference?

Key System Functionality is seen when each business phone or extension connected to your business phone system is able to have a button (called Line or CO Button) dedicated for each Phone Line that you have for calling out i.e. the local telephone company or CO lines.

When you press this Line Button on your phone, you are actually connected to one of the CO Lines from your phone company.

Lets say you have subscribed for 4 business telephone lines from your local phone company then you will have Line 1, Line 2, Line 3 and Line 4 Buttons on your business phone.

You are able to pick and choose what ever line you want to dial out. Also if one of the lines is faulty you will actually hear a crackling or if it is dead then you will hear nothing except a slight hiss. In short you are able to SEE all your lines coming into the office.

You are also able to see the status when someone in the office is using any of the CO Lines, because the corresponding Line Button will be lit up RED or have a Black Triangle against it (this feature is available in all business phone systems with slight variations.) If you press this Lit up Line Button, it will beep at you and if you have a display, it will show you the current status as LINE BUSY.

Based on my experience in the practical world, KEY Telephone Systems HAVE All and more features than PBX phone systems.

In fact this very feature of Having Line Buttons or Line Presence is a HUGE factor for most small businesses who usually have about 3 to 8 CO Lines and about 3 to 25 phones.

And what is a PBX Telephone System?

In fact, the PBX Telephone System, in the practical sense, does not have the Line Presence feature or CO Line Button feature at all!

Which makes the PBX System a bit inferior when compared to a Key Telephone System. Doesn’t it? Well, take my word..this is true. Key Telephone Systems have all the features you will possibly need, whether you are a big business or a small business.

It is true, though, that if you are a very very large business , like Microsoft, or GE or AT&T etc. i.e if you need lots and lots of CO Lines than the number of buttons on your business phone, then you would go for a pure PBX Telephone System.

(That doesn’t mean you cannot use a Key Telephone System for large organizations…Key Telephone Systems can be SETUP as PBX systems, but PBX systems CANNOT be setup as Key Telephone Systems.)

How do you setup a Key Telephone System as a PBX?

Very simple. Just remove all Line Buttons from your Key Telephone, and use “9” on your dial pad to get the first available line to dial out. That’s the exact difference between an IP PBX and the Traditional Phone System. You will not be able to put a line on hold at one phone, and take it on another phone. Simply because you do not have individual line buttons on an IP PBX Phone.

A PBX or Private Branch Exchange, is a business phone system that doesn’t need the ability to have Line Presence on all its business phones or extensions. Now there are technical differences in how they work, as a switch, etc etc. but when it comes to your understanding,that is the KEY feature.

Both phone systems have the ability to handle multiple lines, multiple conversations, auto-attendant, voice mail boxes, for a wide range of office sizes.

The critical point is that most of the IP PBX Systems or IP Phone Systems or VoIP Phone Systems DO NOT have the Line Presence feature.

And if you think that’s important to you, just like our last client did, then please don’t opt for the IP PBX System! VoIP PBX or IP PBX may not be for everybody.

But if you do need some great features, unlimited voicemail ports, voice-mail to email, unlimited extension capability, menu driven web interface for programming, call centre features, off-site remote extension included in the base price, then this is the system for you.

Advantages and Disadvantages of Prepaid Cell Phones

We are constantly seeing advertisements on TV promoting cell phones and cell phones carriers with what they call great introductory offers if you sign up with them on their network.

Is it worthwhile signing a one-year contract with a cell phone carrier?

Well that is a question that you need to answer for yourself, while the pricing may look attractive you need to consider if you will be using the phone on a regular daily basis. Ask your self the following:

·Do I need my cell phone for work?

·Will I be calling mainly friends and family?

·Will I be making out of state calls or international calls?

If the answer to the above number of questions is no, well prepaid cell phones could be your best choice. Prepaid cell phones are ideal for people who do not intend signing contracts and do not intend to use the cell excessively. There many advantages and disadvantages with using this type of cell phone:

Advantages of using a prepaid cell phone:

·No credit check required

·No deposit required

·No monthly rental fee

·No termination fee if you decide not to use your phone again

·No service fee

·A large selection of phones available including camera cell phones

·Always in control of call costs

Disadvantages of using a prepaid cell phone:

·Calls and SMS Text will be more expensive per minute than using a bill phone

·You could run out of credit at a crucial time that you need to make a call

·Some carriers will put a time limit on your credit (you will need to use it up within a certain time or else it will be classed as invalid)

Children with prepaid cell phones:

Always purchase a cell phone with low emissions for health and safety purposes. Children under the age of 7 are not recommended to using any type of cell phone.

If you like to keep tabs on your children and you feel a cell phone is a good safe idea, do not make the mistake that many parents do in giving a cell phone that has line rental. If you do this be very prepared for a large monthly bill every month from the mailman. It’s like giving your child a large bag of candy and asking them not to eat them unless it’s really necessary. Prepaid cell phones are ideal for children, if their credit runs out, so be it, but you can always call or text them and it’s then up to you what extra credit to allow.

It’s very difficult for young children to budget wisely and kids will be kids so you need to careful when it comes to financing them a cell phone.

What are the highest costs involved with prepaid cell phones?

Be careful your credit can be eaten up very quickly. Camera cell phones are great fun and handy to have at times but if you are using a prepaid cell camera phone and want to text photos the cost can be very high per text. Also watch for roaming charges are these too can be very expensive. Always look for promotions and giveaways with no hidden charges.

Is getting credit easy?

Buying credit could not be easier. Most stores will sell credit for the different cell phone carriers and some stores have vending type machines where you can simply follow the instructions and top up your credit. You can also call your cell phone carrier (usually a toll free number) and purchase with your credit card. Credit issued as a long number. Simply type this into the correct section of your cell and that’s all there is to it.

Prepaid cell phones in brief:

·A great idea for those of us who need to stay inline with our phone expenses.

·Very handy to have for emergencies with no rental charge.

·Ideal for children if you wish for them to carry a cell phone

·A good back up if you experience a problem with your house phone

Once again always look into the different cell phone carriers and their prepaid cell packages, not all are the same with some giving excellent starter packages.