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Introduction to Voice over IP (VoIP)

By On July 11, 2012 · In Asterisk, Mobile VoIP, Open source, SIP protocol

One important step into adopting VoIP is to choose a VoIP service, which will allow you to make and receive cheap or free local and international phone calls. It is important to choose the right type of VoIP service. Your needs and the way you will communicate should help you decide which type [...]

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free phone calls

How to configure Internet tel. and SIP settings on Nokia phone (E52)

By On March 28, 2012 · In Google Voice, Mobile VoIP, Open source, SIP protocol, Symbian, VoIP calls quality

In this article we will talk about Nokia Internet telephony and SIP settings since many people asking me about that. I have check all configuration myself on my old Nokia E52 as well as E71 buddy and everything works fine. Therefore you can use the same setup procedure on any E-series with Symbian.

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History: Kellogg Field Phone (World War I)

By On October 19, 2011 · In History, Mobile VoIP, SMS to email

Ask people familiar with telecommunications history and they’ll tell you that the first text message sent from a mobile phone was sent in 1993. But there was  a phone that sent text messages more than 75 years before that! Amazing, bu the Kellogg Switchboard Supply Company field phone, model 1917 (and [...]

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G.711: u-law or a-law?

By On August 23, 2011 · In Asterisk, Google Voice, Mobile VoIP, QoS - Quality of Service, VoIP calls quality

As you already know G.711 is a high quality voice codec that we have support for in Asterisk as well as in  many other open source and commercial VoIP platforms. G.711 uses logarithmic PCM (pulse code modulation), a standard as old as from 1972. G.711 is pretty much the norm for IP-telephony where there is enough [...]

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Wi-Fi access point/router optimization for VoIP and other real time apps

By On August 23, 2011 · In Mobile VoIP, Prioritization and traffic shaping, QoS - Quality of Service, SIP protocol, VoIP calls quality, VoIP over VPN

In order to improve the bandwidth allocation for certain apps in your wireless network you need to enable QoS (quality of service) feature on your router/access point. Please make sure that you have enough bandwidth available (down and up) on your [...]

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Microsoft enabling the ability to eavesdrop on VoIP conversations

By On July 13, 2011 · In Asterisk, Mobile VoIP, SIP protocol

I’ve reading an interesting article on eweek.com that describes the problems that large companies face as they try to diversify – specifically the move of Microsoft from software towards IP telephony.

News Analysis: Now that Microsoft is on its way to becoming a telephone company, it is finding itself subject to a lot of things that a [...]

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Nimbuzz growing even without Skype

By On June 24, 2011 · In Android, Asterisk, Mobile VoIP, SIP protocol, VoIP calls quality, VoIP over VPN

According to Nimbuzz, since July of 2010, they have more than 28 million new users joined their network. That amounts equals to 100,000 new peoples for every 24 hours and they’ve doubled in size in year to 50 million users.

Even with Skype integration removed, Nimbuzz still supports Facebook, Yahoo, Windows Live, Google Talk, AIM, and [...]

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How to make your VoIP calls private and confidential

By On June 21, 2011 · In Asterisk, Mobile VoIP, Prioritization and traffic shaping, SIP protocol, VoIP calls quality, VoIP over VPN

There is no doubt a chance exists that your IP phone calls can be tapped and listened to. We will discuss here how to make sure your calls stay private and secure.

The possibility your VoIP calls being monitored is much higher then of conventional phone calls. The reason for this is that IP telephony [...]

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Think on solutions: VoIP phone system

By On June 21, 2011 · In Android, Asterisk, Mobile VoIP, Prioritization and traffic shaping, QoS - Quality of Service, SIP protocol, VoIP calls quality, VoIP over VPN

It is often taken for granted that installing VoIP solutions will save customers time and money, but in actual fact getting Return on Investment depends on a number of factors.

Firstly if you are planning to use VoIP phone system for business purposes, think about how it will integrate into your existing Public Switched [...]

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Asterisk and Google Voice

By On June 21, 2011 · In Asterisk, Google Voice, Mobile VoIP, Open source, SIP protocol

Asterisk: How to make calls using Google Prerequisites

Asterisk can communicate with Google Voice and Google Talk  using the chan_gtalk Channel Driver and the res_jabber  Resource module. Please ensure that both are compiled and part  of your installation prior following the configuration guide  below. Compilation of res_jabber and chan_gtalk for use with  Google [...]

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VoIP Codec: Payload size

By On June 16, 2011 · In Asterisk, Mobile VoIP, SIP protocol, VoIP calls quality

The size of the payload of each encoded voice packet influences two things: lag and bandwidth.

Every encoded packet that is sent incurs fixed bandwidth overheads (due to IP and other headers added to the data in the network). Thus, larger payloads incur a proportionately smaller overhead, thus reducing the nominal bandwidth utilisation. However, by [...]

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Nokia SIP settings

By On June 16, 2011 · In Android, Asterisk, Mobile VoIP, SIP protocol, VoIP calls quality, VoIP over VPN

Nokia setup for SIP-based VoIP service

UPDATE: New article about SIP settings (Internet tel.) for Nokia E52 is here

Now you can enjoy crystal-clear phone calls over the Internet using the new Nokia S60 phones. If you have access to a Wi-Fi or 3G connection, you can [...]

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VoIP client behind a VPN with DD-WRT

By On June 14, 2011 · In Asterisk, Mobile VoIP, QoS - Quality of Service, SIP protocol, VoIP over VPN

We have two sites with local networks interconnected by VPN tunnel and we have a VoIP server at one of the sites. The server side based on a PC with Windows 2003 Server (also acting as VoIP and VPN server) installed. On the other side we have a DD-WRT as the VPN client.

As we [...]

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Mobile VoIP – the future of mobile communications

By On June 13, 2011 · In Android, Asterisk, Mobile VoIP, SIP protocol

 

The vast potential of VoIP for businesses has already showing its signs of gaining importance in corporate market in last decade including “The disruptive” call center and outsourcing who partially or completely relaying on VoIP based services for they service offerings.

The new ” Cool corporate stuff ” for the market is [...]

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Sip on Android

By On June 10, 2011 · In Android, Mobile VoIP, SIP protocol

There is a very interesting project started recently, called Sipdroid – VoIP software for Google Android operating system using SIP (Session Initiation Protocol) and it’s actually Java SIP stack contributed by MJSip.

Sipdroid is open source free software released under the GNU General [...]

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Typical VoIP Problems: not right codec, packet loss, jitter, out‐of‐order packets

By On June 9, 2011 · In Asterisk, Mobile VoIP, Prioritization and traffic shaping, QoS - Quality of Service, SIP protocol, VoIP calls quality

Due to human perception, VoIP is much more sensitive to certain network conditions that are considered well within spec for most applications.

Network issues such as packet loss, jitter, and packet sequence errors are inherent to IP networks, and are well corrected and tolerated by data transfer protocols. Voice transmissions are real‐time by the nature; [...]

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