By Mansi Aggarwal

VoIP or Voice over Internet Protocol is a technology that taken the telecom industry by storm by introducing significant changes in the field of telecommunications. Because of the changes it has brought to the traditional telephony system it has become a hot favorite in both the residential and commercial market.

Voice over Internet Protocol (VoIP) is basically a process, which converts your voice into digital signals that travel over internet. Its most prominent feature is its affordability. With VoIP you can make long distance calls at a fraction of cost that you used to pay to your telephone companies. It is primarily because of the fact that transferring digital signals over internet is quite cheaper than transferring analog signals over the traditional telephone lines.

The VoIP hardware needed to make VoIP calls depends on the type of VoIP service being used. VoIP service is available in three different modes. These are ATA, IP phone and PC-to-PC. All these services are common and available for the use at the home PC. ATA or Analog Telephone Adaptor lets the user to connect the regular telephone to the computer and use it for VoIP service by converting analog sound bits into digital data. Internet Protocol phones are those phones which are specially designed to be used with VoIP service. They look very similar to the standard phone models but their components are different from them. Moreover, a cordless IP phone will enable the user to use the VoIP services on the move. The PC-to-PC VoIP can be set up by installing the software provided by the VoIP service providers. Yahoo and MSN messengers are the examples of such software. In the PC-to-PC VoIP, users can make long distance calls through their computers and can communicate through the headphones with attached microphones.

As the VoIP is gaining popularity the market for the VoIP services and hardware is becoming more and more competitive. Presently there are several companies that are offering VoIP services and hardware to the growing market for the VoIP. However, the VoIP technology is so new that even the latest VoIP hardware becomes outdated in few months. Thus, one needs to be very careful while investing in the VoIP hardware. First of all, you should decide what kind of VoIP service is perfect for you. Then compare the cost of the VoIP hardware with that of the traditional phones. If it costs more than the traditional phones then there is no use of buying it as it is not advisable to buy VoIP equipment just for the sake of having the latest technology. Moreover as the products become outdated very fast you should purchase them only when needed. If you are using VoIP then you should be ready to spend more money in future to upgrade your hardware. Also, the installation costs are to be paid every time you change or upgrade your hardware. Finally, before going to shop for VoIP hardware you must collect information about the different vendors and should only select a licensed or authorized dealer.

By Jason Cole

Moving on down the line, today we continue our series on audio effects and editing tools. In the past few articles we’ve such effects as reverb, flange, delay, and noise gate. If you enjoy dabbling in audio production, you’re going to enjoy today’s article. We’ll be discussing compression, which is instrumental in the audio production arena. And also we will also be discussing ring modulation, which is a bit more fun and flexible audio effect. So, in today’s article get ready to learn about both, compression, and ring modulation. Let’s discuss how these effects work and why they work the way they do.

Compression
Compressors reduce the dynamic range of an audio signal, if its amplitude exceeds a set threshold. The amount of range reduction is determined by a set ratio. If the ratio was set to 6:1, the dB would need to be increased by 6 to increase the output signal by 1 dB over the threshold. The way that a compressor reduces dynamic range is by using a variable-gain amplifier, which reduces the gain of an audio signal. Analog compressors typically carry this out by using a voltage controlled amplifier, which reduces the gain as the input signal’s power increases. Digitally, compression is carried out via DSP (digital signal processing), and this is the most modern version of the effect. The main use of compression is to make music sound louder without increasing its peak amplitude. Compressing the peak, (loudest signal), allows you to increase the overall gain without exceeding the dynamic limits of your reproduction device. Compression is widely used in TV and radio, allowing maximum perceived volume, without going over the strict limits imposed by most broadcasting companies.

Ring Modulation
Ring modulation is achieved by multiplying two audio signals, with one signal being a simple waveform such as a sine wave. They combine the two signals, outputting the sum and difference of said signals. Ring modulation is related to amplitude modulation and frequency mixing, and it produces a signal rich in overtones. It is well suited to produce metallic and bell-type sounds. Modern ring modulators, like modern compressors, use digital signal processing to produce the effect. Using DSP to do this produces a mathematically perfect signal output, which some musicians do not like. You can come up with some interesting harmonics using a ring modulator by changing the frequency of the two input waveforms.

This is the third installment in my continuing series on audio effects and engineering tools. We discussed compressors and ring modulators today, a couple of very interesting and deep effects. I learned a lot myself, so I hope that you did as well. We will be continuing this series indefinitely, until we run out of effects! I hope that this has shed a little light on these two amazing pieces of equipment, ultimately making your next music project a bit more interesting and productive.

By Jason Morris

Analogue is the process of taking an audio or video signal and then turning it into electronic pulses. Digital is the process of turning the signal into a binary format, represented by a string of 1’s and 0’s. Analogue technology has been around for a long time now. It really isn’t that complicated and is fairly inexpensive. The problem with analogue signals lies in their size limitations regarding the amount of data they can carry.

Because of the way digital works by breaking a signal into 1’s and 0’s and then re-assembling it exactly at the other end, it gives you clear and distortion free cordless conversations. A digital signal knows what it should be when it reaches the other end, through the arrangement of the binary code. This means it can correct any errors that may have occurred during the transmission of the data (signal). All this means that in most cases clarity of the signal is maintained, offering distortion free telephone conversations or clearer television pictures.

Digital technology is also more compact, allowing you to cram much more data into the same space as an analogue signal, meaning more features can be crammed into the digital signal. Though digital signals offer great clarity, they don’t always offer the same rich sound quality as analogue for now.

Cordless phones

Because of the way digital works by breaking a signal into 1’s and 0’s and then re-assembling it exactly at the other end. It gives you clear and distortion free cordless conversations. Digital cordless phones also encrypt the binary data during transmission, making your call safe from eavesdroppers. With digital more power can be applied to the signal allowing you greater range on cordless conversations.

If you are in a small office or in your home, it may be that you don’t require a big range and security isn’t an issue, in which case you may find that a cheaper analogue cordless system will fulfil your needs. Check out the features at the end of this article to help you decide if a digital cordless phone will benefit you. You will need to keep in mind that when using digital or analogue signals for cordless phone calls, the handsets themselves are still analogue devices that can only be used on analogue lines. Also the range of your cordless phone, whether using analogue or digital signals will always depend on the environment in which you are using it.

Phone systems

When considering which type of phone system is best suited to your business, digital or analogue. Many companies are now choosing hybrid systems, which allow you to use both digital and analogue peripherals, giving you the benefits of a digital system while offering the flexibility to implement any existing analogue equipment.

Benefits of digital and hybrid phone systems

1. Computer Telephony Integration (CTI) – Digital systems allow better implementation of Desk Top Assistant (DTA) software.

2. Allow you to integrate your telephone system with your computer network.

3. Offers greater clarity of call signal (no distortion).

4. Easily adapts to the use of DECT cordless technology, giving your employees the freedom to roam, while still receiving a clear distortion free signal.

5. Allow better integration with advanced features such as voicemail auto attendants and other call handling features.

Benefits of digital handsets

1. Allow better integration of advanced features such as voice mail and auto-attendants.

2. Offer greater internal memory for better call handling.

3. Caller Line Identification (CLI). Allowing you to view the identity of any callers before answering the call.

4. Offer clear distortion free calling.

5. Offer high capacity name and number directories.

Benefits of digital (DECT) cordless handsets

1. DECT cordless offers increased range over analogue sets. Up to 50m indoors and up to 300 outdoors, which can be increased with the use of strategically placed repeaters.

2. DECT cordless offers better security through signal encryption, stopping eavesdroppers.

3. Offer clear distortion free calling.

4. Allows the use of extra handsets without the need for extra wiring.

5. Calls can be transferred between handsets.

6. Caller Line Identification (CLI). Allowing you to view the identity of any callers before answering the call.

7. Offer high capacity name and number directories.