Why You Need a SIP Address to Make Calls Over the Internet

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If Voice over Internet Protocol (VoIP) software is like a virtual ticket for your voice to travel anywhere, a Session Initiation Protocol (SIP) address is the digital passport that gets its through the airport gates.

On the one hand, VoIP technology enables voice communication via the internet by converting audio into data packets that can be sent through internet signals.

On the other, a SIP address is a unique identifier for that data in the digital communication world. It lets you make and receive calls using VoIP software by facilitating the initiation and termination of online voice transmissions.

As such, SIP addresses are necessary for making calls over the internet.

SIP server graphic showing how the system works from Nextiva.

SIP Address and SIP URI

Understanding SIP addresses requires understanding uniform resource identifiers (URIs) as well, because a SIP address is itself a URI that provides key information for SIP networking to function.

SIPs are responsible for initiating, modifying, and terminating video, voice, messaging, and other communication channels, and SIP calling relies on many different components for these functions, including SIP servers, proxies, and user agents. In order for all of these elements to work, there needs to be a way of identifying specific users and/or telephone number extensions on a VoIP system.

That’s where URIs come in.

While it’s true that the SIP address is what lets you participate in SIP-based communication, it’s often expressed as a SIP URI. This is what the protocol uses to identify resources and participants in SIP communication.

Out in the wild, the basic syntax for this looks like sip:username@host, and some examples are as follows:

In an address like sip:[email protected], each component has a different function on the system’s backend.

  1. sip: A prefix is what specifies the communication protocol, which in this case is obviously SIP.
  2. alice: A username that identifies the specific device or endpoint within the domain.
  3. A domain name or address that points to the server where the user is registered and can be reached.

Together, these parts work to ensure SIPs route and process the SIP addresses properly and that the right user is reached at their designated domain.

How Is a SIP Address Different from an Email Address?

It’s no secret that SIP addresses can look like email addresses, but they’re used for different purposes and associated with different communication protocols.

Here’s a breakdown of the main differences between SIP and email addresses:

  • Communication protocol: Email addresses are used for communication via the email protocol (SMTP or Simple Mail Transfer Protocol) to exchange emails that include text, attachments, and multimedia content. SIP addresses are used for real-time multimedia communication via the Session Initiation Protocol.
  • Communication medium: Email addresses are mainly used for asynchronous communication, where messages are sent and received with a potential variable time delay. SIP addresses are designed for synchronous communication, such as voice and video calls.
  • Format: Email addresses typically use the format [email protected]. SIP addresses employ the format sip:[email protected], which is similar to email but includes the SIP protocol component.

In short, a SIP address such as sip:[email protected] indicates that there is a SIP Proxy server named with an account named alice used by a certain person or device for participating in SIP communication sessions. It may also be true that the same end user has an email address of [email protected], but it’s not guaranteed.

Is a SIP Address Free?

Oftentimes, yes.

Many providers offer free SIP accounts that let you make online voice and video calls without paying a nickel. When you set up a free account, your SIP address will be associated with the particular provider’s SIP infrastructure.

If you have serious technical skills and want to maximize your control, you could also consider setting up your own SIP server. In this case, you would need to create and assign SIP addresses for each additional user.

Nevertheless, with free SIP calling comes certain limitations, like limited or nonexistent access to any features you don’t pay for. These can include restrictions on call lengths, for example.

Businesses that rely on voice and video calling usually opt for paid SIP services over free plans. This gives them benefits like unlimited call durations, enhanced reliability, access to better customer service, and additional features.

When you add up the savings from SIP calling versus traditional phone lines, the cost for paid subscriptions makes a lot of sense. A copper wire phone line can cost between $20 and $50 per month. Meanwhile, SIP lines come in at around $10 to $30 per month.

Getting a SIP Address

Obtaining your SIP address and starting to make calls is pretty simple.

Here’s what you’ll need:

  • An internet connection: You’ll need a reliable and stable internet connection to make sure you have clear, uninterrupted calls.
  • A microphone and a speaker: Whether you’re using a computer or a smartphone, be sure your microphone and speaker are fully functional.

Along with the above, you’ll need a SIP client. This can include a software application or a hardware device that lets you make SIP calls.

There are many different kinds of SIP clients available online through today’s best VoIP providers. Here’s an overview of the options you can expect to find and what they are like:

  • Open-source SIP clients are free, customizable software applications for SIP communication.
  • Enterprise-grade VoIP solutions offer SIP services tailored to business needs.
  • Cloud-based VoIP platforms provide SIP solutions hosted in the cloud for scalability.
  • Mobile SIP apps are smartphone applications for on-the-go SIP communication.
  • Softphones are software-only telephone services that provide user-friendly software for SIP calling. There are both free and paid softphone solutions available.
  • Business communication services frequently include comprehensive SIP solutions for organizational needs.

Once you’ve sorted out your client, you’ll need a SIP address to make calls over the internet. The good news is that you’ll automatically have your SIP address as soon as you choose a client and get it set up.

Thus, with your new URI in place, you’ll be all set for liftoff on your global communications journey.

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