SIP • Last Updated 9/29/2023

VoIP Origination and How VoIP Numbers Work

Even though a VoIP number functions the same as a phone number, VoIP origination offers features that an ordinary number doesn't.

By Josh Whitaker

VoIP number graphic banner

In telecommunications, Call Origination is a core concept, and is simply understood when explained well. Call origination essentially describes your carrier’s process of connecting calls to you. Simply put, origination is incoming calling. But what exactly is going on when a voice over internet protocol (VoIP) call is made? Where do phone numbers fit into the world of internet-centric telecom? Let us answer some of these questions for you.

How does VoIP Origination Work?

In the past, phone calls were made exclusively over the public switched telephone network (PSTN). On the PSTN, a mechanical switch in the phone was used to connect the line, and calls were routed through central offices that used switches to route calls to the proper recipients. In the 1980s and 1990s, telecommunications started to go digital, but the PSTN still relied on circuit-based technology (while the internet utilizes packet-switching technology).

Today, calls can be sent over the public internet or private IP using VoIP. Call origination begins on the PSTN, when an internet telephone service provider (ITSP) uses packet switching technology to convert the audio signal into digital packets of data for transmission over the internet. ITSP companies utilize a VoIP technology - like session initiation protocol (SIP) - to connect your PBX or older telephone system to other callers when you make and receive calls.

From an end-user perspective, the experience of making a call on VoIP is exactly the same as making a call entirely on the PSTN - the caller dials a phone number and waits for it to be answered on the other end. The difference lies in how phone numbers are used, and how the calls are connected.

How do VoIP Phone Numbers Work?

In IP communications, the number is just an identifier for making calls on the network. It is possible for one number to be attached to multiple devices, and a user can make and receive calls from the same VoIP number using their smartphone, desk phone or any other internet-enabled device.

Even though a VoIP number functions the same as a traditional phone number for most users, there are some things that a number can do on an IP network that an ordinary phone number can’t.

Since VoIP numbers can be attached to multiple devices, service providers can offer configurations that use a single phone number to ring multiple devices simultaneously or that will ring each device attached to the phone number one after the other (often called find me/follow me). This feature is particularly useful for customer service call centers or sales teams.

Additionally, given that VoIP utilizes distributed IP networks, area codes have no real significance in assignment of these numbers. However, a device can be assigned a phone number with an area code, regardless of the physical location of the device. In this way, businesses can provision numbers for each of the areas they do business and prospective customers have a familiar, local number to call.

Virtual numbers can also be created to protect the real phone number of a caller for anonymous calling and improved security.

Lastly, since VoIP operates on a data network, the same service can be used for real-time communications that require data transfer, like video calls.

How to get VoIP Numbers

Getting VoIP numbers is as simple as finding an ITSP or VoIP provider to provision and service numbers. Phone numbers that are currently assigned to PSTN landlines or other carriers can be brought onto the network through a process called number porting.

If you don’t have existing numbers you can provision new ones from your provider. Different providers will have different phone numbers available but some may not have number coverage in certain countries. Also, not all carriers offer all of the functionality that’s possible with VoIP numbers, so it’s important to ensure that a provider offers the functionality and regional numbers you require.




Get phone numbers on demand with Telnyx. Instantly search, provision, and port local, mobile, national, and toll-free numbers globally. Telnyx services numbers across 20,000 North American rate centers and 60 countries. Telnyx boasts a global infrastructure that delivers the best in call quality and security. Contact our customer success team to learn more.

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