The VoIP market is estimated to reach $194.5 billion by the end of 2025. This shows that businesses and individuals are rapidly moving forward to an affordable and flexible solution. 

But you might still rely on your old analog phone. Still, no worries; a VoIP adapter is available as a bridge between analog telephone services and the Internet. It simply connects your traditional devices to the internet, which enables you to make VoIP calls. 

Keep reading to understand in-depth about VoIP adapters, how they work, the best VoIP adapters, and how to choose the best fit for your business. 

KEY HIGHLIGHTS

• VoIP adapter is a hardware device that is used to connect conventional devices to the internet. 
• Primarily, there are two types of VoIP adapters: Single FXS and Dual FXS. 
• An adapter works by converting analog voice signals into digital data and transmitting it over the internet to the VoIP service provider.
• Obihai, Grandstream, Cisco, Ooma, and Patton are some of the popular names in VoIP adapters. 

What Is a VoIP Adapter?

A VoIP adapter (also called an ATA—Analog Telephone Adapter) is a device that connects traditional analog phones to the internet. It enables them to make and receive calls over VoIP (Voice over Internet Protocol) networks instead of traditional landline services.

Moreover, VoIP phone adapters are suitable for both home and office use. Adapters are easy to set up and can be used in the existing device. 

Types of VoIP Adapters 

There are two types of VoIP adapters: Single FXS and Dual FXS. Both of these are based on their port system. 

• Single FXS VoIP Adapter:  A single FXS VoIP adapter has one port, so you can connect only one phone or landline at a time. It’s a good option if you only need to link one old phone to your VoIP system. These adapters are affordable and great for small businesses or people who work from home.
• Dual FXS VOIP Adapters: A dual FXS VoIP adapter has two ports so that you can connect two devices, like phones or fax machines, at the same time. This is helpful for businesses or anyone who needs multiple devices connected to their VoIP setup, offering more

How does a VoIP Adapter Work?

A VoIP adapter connects your traditional landline phones to the voice over Internet protocol (VoIP). 

This technology enables you to use a standard phone to transmit voice over the Internet by converting the phone’s analog signal into digital data packets.

When you make a call, the adapter converts your phone’s voice signal into a digital signal and sends it over your internet connection to the VoIP service provider, which routes it to the person receiving your call.

When you receive a call, the process is reversed — the digital data is converted back into an analog signal so that you can listen to the voice through your device. 

Most VoIP adapters plug into both your internet router and your telephone. Some models are also available that support Wi-Fi for wireless use.

With this, you receive low-cost calling, greater flexibility, and the ability to access VoIP features and avoid replacing the existing devices. 

Benefits of Using a VoIP Adapter

A VoIP adapter lets individuals and businesses utilize VoIP services on traditional devices, which saves costs and offers higher flexibility. 

Here are the benefits of using a VoIP adapter:

• Cost-saving: VoIP uses the internet for calls as opposed to conventional phone lines, resulting in considerably lower than traditional landline phone bills. Also, you don’t need for pricey equipment.

• Flexibility: You can call from any location, which is very useful for remote workers and multi-branch businesses. It enables employees to connect and work more effortlessly with others.

• Easy to move:  With VoIP operating online, there’s no need to transport heavy equipment when you move. This allows your business to relocate smoothly and without complications.

• Scalable:  Setting up VoIP systems doesn’t involve extensive wiring or hardware. As long as you have VoIP-supported devices, you don’t have to rewire any hardware, such as phones or headsets.

•  Advanced Features: With VoIP adapters, you get access to advanced telephony features that are not compatible with traditional phones. The features include call forwarding, voicemail-to-email, and multimedia messaging to improve productivity. 

5 Best VoIP Adapter in 2025

As there are multiple VoIP examples in the market, the same goes for the adapter. The right VoIP adapter can make a big difference in call quality, reliability, and overall efficiency in VoIP conversations. Based on our research, here are the 5 best VoIP adapters: 

1. Obihai OBi300 Single Port ATA

Obihai OBI300 is a single-port analog telephone adapter. It is one of the best VoIP adapters because it supports the use of analog devices with most of the SIP trunking providers. 

You’ll receive both: simplicity and convenience in setting up this adapter. When using Obihai with an SIP service provider, you can access speed dial, message waiting notification, call forwarding, recording, history, and other features. It can be the best solution for businesses or individuals looking for a mini-phone system. 

Key Features

• Zero Touch configuration through HTTPS redirects to the SP server.
• The OBiTALK portal simplifies configuration without hassle.
• Includes a USB port and OBiWiFi dongle for flexible wireless use.
• Supports 4 SIP accounts.
• Provisioning via HTTP, HTTPS, or TFTP. 

2. Grandstream VoIP Adapters

Grandstream VoIP adapters are quite popular as they are reliable and come with advanced functionalities. Likewise, the Grandstream HT813 is one of them that provides one FXS (Foreign Exchange Subscriber) port and one PSTN line FXO (Foreign Exchange Office) port. 

This integration allows calling to and from the PSTN line. Using this adapter, users can switch from analog to VoIP technology. Similarly, Grandstream Hybrid ATA with FXS and FXO Ports adapter offers advanced VoIP features along with robust security for high-quality IP service. 

Moreover, it supports security certificates based on per unit and offers AES encryption, which makes Grandstream VoIP adapters a good choice. 

Key Features

• Provides FXS and PSTN FXO ports for easy connection.  
• Offers HD voice quality with lifeline backup.  
•  Supports calls on both PSTN and VoIP using one analog device.  
• -Includes dual 100Mbps LAN and WAN ports for fast internet.

3. Patton SN101 SmartNode Single FXS Port ATA

Patton SmartNode is another VoIp adapter that has one FXS port. That means it can only integrate either fax machines or analog telephones into your VoIP systems. Users receive a broad choice for VoIP platforms as it supports open SIP conversation protocols. Additionally, Patton supports features ranging from call forwarding to high-quality, reliable sound, and more. 

Key Features

• Provides password protection and a simple web setup.
• Supports 3-way conference calls.
• Small and easy to place anywhere.
• Audio Codecs: G. 711μ/a, G. 723, G. 726, G. 729.
• Fax over IP: T. 38 support, G. 711 pass-through.

4. Cisco SPA112

Cisco SPA 122 is a small designed adapter that can handle international voices more efficiently. It helps businesses to offer the best interaction for customers as well as employees. It works well for homes, offices, and small VoIP businesses in a full IP setup. It’s easy to use and offers advanced features to keep employees and customers connected to a secure Cisco network.

Key Features

• Secure and clear calls with advanced features.  
• Great sound quality with smooth two-way audio.  
• Perfect for home or office use.  
• Handles two phone lines for extra convenience.  
• Quick and easy setup with plug-and-play design.

5. Ooma Telo Adapter

Last on our list, the Ooma Telo VoIP adapter is especially for home or remote workers. With the right tools and practical tips, remote work becomes easier. The best thing about Ooma is their connection with high internet speed and offering of an easier installation process in no time. 

Being a wireless accessory VoIP adapter, it connects phones through a Wi-Fi network to the Ooma Telo base station. In addition, you can also connect this adapter to your mobile phone, which allows you to reply to incoming calls anytime. 

Key Features

• Works smoothly with WiFi.
• Makes international calls cheaper.
• Includes VoIP features like call forwarding, call waiting, and blocking spam calls.
• Has an easy-to-use mobile app for calling and settings.
• Provides clear, high-quality sound for calls.

Choosing the Right VoIP Adapter

Getting yourself the best VoIP adapter can be hectic work. If you are planning to use a VoIP Adapter for your VoIP phone, then you should keep these things in mind:

• How many devices is your requirement? : Make sure how many telephones you will use and if they are faxes. One FXS port can be enough for a single phone, but when used for multiple phones or faxes, the need for an FXS port rises.

• Features: Finalize your objective behind the adapter. If you require advanced features, then research the adapter offerings; you might also need to go a little ahead of your budget. 

• Do you require a router to make it work? When needing a router for VoIP service or lacks an ethernet port, you’ll need a VoIP adapter that comes with an in-built router. 

• Compatibility: Make sure to see if the VoIP adapter is compatible with your existing phone systems and devices. Research if it supports SIP protocols and can be integrated with your network or not. 

Conclusion

A VoIP adapter is a device that helps you to use the internet on your analog device. It lets you enter the modern system with access to a range of features. With the right adapter, you can ensure clear calls, easy setup, and top-notch interactions. 

Obihai OBi300 Single Port ATA, Grandstream VoIP Adapters, Patton SN101 SmartNode Single FXS Port ATA, Cisco SPA112, and Ooma Telo Adapter are some of the popular options in the market.

However, you can find the best suit for your business with proper research and comparisons of different adapters. 

FAQs

What is the VoIP used for?

Voice over Internet Protocol (VoIP) is a technology that allows you to make voice calls through an internet connection instead of an analog phone line. 

How to configure a VoIP adapter?

To configure a VoIP adapter, start by plugging into the power cable and turning on the adapter. After powering up, you’ll need to access the configuration interface ( typically web-based). This is done using a computer that’s connected to the same network as an adapter.

After that, you’ll need to follow the instructions provided by your VoIP service provider. 

Do I need a voip adapter?

You might need a VoIP adapter if you use Voice over Internet Protocol (VoIP) service unless you have a proper VoIP-compatible phone.