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An analog telephone adapter (ATA) connects an analog phone or other analog telephony device to an IP-based phone service. Typically, the phone plugs into an FXS port and the adapter connects to the network through Ethernet. The ATA provides the bridge; it does not include phone service or internet access.
What an ATA does
An ATA lets analog equipment participate in an IP telephony system. It provides an analog phone connection on one side and a network connection on the other, handling the telephony signaling and call transport required by the system. Cisco describes its ATA 191 as a telephony-device-to-Ethernet adapter for using regular analog phones on IP-based telephony networks (Cisco ATA 191 data sheet).
The adapter must work with a compatible service or call-control platform. SIP is a common protocol for signaling and session management: Cisco’s ATA 191 administration guide explains that SIP helps establish, maintain, and terminate calls in an IP telephony network (Cisco ATA 191 administration guide). Protocols, supported codecs, and provisioning vary by model and provider, so an Ethernet jack alone does not establish compatibility.
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FXS and FXO: which port do you need?
FXS and FXO refer to opposite ends of an analog telephone connection. Match the port to the equipment and call path you are connecting.
#1 Best Overall
Grandstream HT802 V2 2 FXS Port Aanalog Telephone Adapter (HT802-V2)
- Supports 2 SIP profiles through 2 FXS ports and a single 10/100Mbps port
- TLS and SRTP security encryption technology to protect calls and accounts
- Automated provisioning options include TR-069 and XML config files
- LED indicators - POWER, NET, PHONE1, PHONE2 Supports 3-way voice conferencing Failover SIP server automatically switches to secondary server if main server loses connection
- Supports T.38 Fax for creating Fax-over-IP
| Interface | Connects to | What it does |
|---|---|---|
| FXS (Foreign Exchange Station) | An analog phone or other analog endpoint | Provides the phone-facing circuit, including dial tone and ring voltage. |
| FXO (Foreign Exchange Office) | A traditional PSTN line or a PBX station interface | Connects the device to the line-facing side of an analog telephone circuit. |
For the common setup of using an analog handset with VoIP, connect the handset to an ATA’s FXS port. If you need to bring a traditional outside phone line into an IP system, the device handling that line needs FXO capability. Cisco documents these roles and connections in its ATA 191 overview.
How to choose an ATA for your setup
- Identify the connection you are making. For an analog phone connecting to VoIP, look for FXS. For a PSTN line connecting to an IP system, look for FXO. A hybrid device may have both.
- Count endpoints and lines. Check the number of ports and confirm that they support the number of analog devices and independent voice lines you need. Port count and line capacity are not interchangeable.
- Check service compatibility. Confirm with the SIP provider or call-control administrator that the exact model and its firmware can be provisioned and supported. Cisco’s ATA 191 documentation lists supported call-control systems, illustrating that compatibility is model-specific (Cisco ATA 191 data sheet).
- Check the attached equipment. If you plan to connect a fax machine, paging system, or another specialized endpoint, verify that its required features work with the ATA and the selected service.
- Plan for the rest of the service. The ATA is a network endpoint, not an internet connection or telephone subscription. Confirm that the site has the required network, power, and phone service.
Examples of different ATA port configurations
These documented models illustrate why the connection scenario matters; they are examples, not universal recommendations.
Quick Recap
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Rank #4
FLYINGVOICE FWR8101 Analog Telephone Adapter, VoIP Adapter with 1 FXS Port, AP & Repeater Mode, 2.4GHz 300Mbps Wi-Fi, Supports T.38 Fax Protocol, Ideal for PBX, SMB, Remote Work & Business Travel
- Reliable ATA with FXS Port & SIP Line: The FLYINGVOICE FWR8101 works as a professional analog telephone adapter with one FXS port and one SIP line, making it easy to connect traditional phones to VoIP networks. A compact VoIP adapter solution for SMBs, enterprises, and remote offices
- AP Mode & Temporary Router: This VoIP adapter doubles as a temporary Wi-Fi router. With AP mode, 2.4GHz frequency, and 300 Mbps speed, it brings network access to co-working spaces, small offices, or field teams that need instant and stable connections. After first setting up, simply plug it in at a hotel or temporary office to set up your own secure mini-network easily
- Flexible Repeater Mode for Wider Wi-Fi Coverage: Use FLYINGVOICE FWR8101 as an analog telephone adapter with built-in repeater mode to extend wireless coverage. Ideal for mobile professionals, co-working spaces, or IT consultants who need strong, reliable Wi-Fi alongside VoIP communication
- Supports T.30 & T.38 Fax over SIP: This VoIP adapter ensures smooth fax transmission via T.30 and T.38 protocols (PBX/ISP registration required). Designed for fax-intensive industries like healthcare, law firms, and government offices, FWR8101 ATA integrates fax machines seamlessly into VoIP networks
- Better for Business Use instead of Home Use: As a business-grade analog telephone adapter, FWR8101 requires PBX or SIP services and is not suitable for casual users. Perfect for IT professionals, system integrators, and enterprise buyers who need a reliable VoIP adapter for advanced deployments
Rank #3
CELL2JACK - Cellphone to Home Phone Adapter, Make and Receive Cell Phone Call on Your landline Phone Free - Cell Phone to Landline Dock - Cell to Landline Converter
- EXTEND CELL PHONE SERVICE TO HOME PHONES: Transform your traditional landline into a smart communication hub. The CELL2JACK cellphone to home phone adapter allows you to use your existing home phones to make and receive mobile calls and access Siri or Google Assistant, all without needing a new phone setup. This Bluetooth landline adapter is ideal for both corded and cordless models, including rotary and senior-friendly phones with big buttons.
- ELIMINATE CELLPHONE RADIATION: Reduce your exposure to harmful cellphone radiation with CELL2JACK cell phone to landline adapter. This innovative device allows you to use your landline for mobile calls, minimizing your exposure to potential radiation that could have cancer-causing effects. It’s a health-conscious choice for any household aiming to decrease electromagnetic pollution without compromising on connectivity.
- SUPERIOR SIGNAL STRENGTH ANYWHERE: Overcome poor cellphone reception with the cell to jack landline adapter. Place your cellphone where the signal is strongest and use your home phone for clear and reliable communication in any part of your house. Our cell phone to landline converter is perfect for homes with spotty cellular coverage, ensuring you never miss an important call due to weak mobile signals.
- ALL TYPES OF TELEPHONES SUPPORTED: The CELL2JACK Cell phone to landline dock supports all types of analog landline phones, including corded, cordless, desktop, rotary, and caption phones. This cell phone to home phone adapter allows you to make and receive cell phone calls with any home telephone, integrating modern mobile technology into every style of phone in your household, allowing you to make and receive cell phone calls effortlessly.
- SMART HOME INTEGRATION: CELL2JACK cellphone to landline home phone adapter enhances your home automation by enabling control of smart home devices via your landline phone. Easily manage lights, fans, TV, and other smart devices through voice commands or phone controls, integrating with both Siri and Google Assistant. This feature brings home automation capabilities through your existing landline, enhancing user convenience and control.
Rank #2
Alrhso 1 Piece Cell to Jack Landline Adapter Analog Telephone Adapter
- Product Dimensions: One analog telephone adapter 3.5x2x1.7cm/1.38x0.79x0.67 inches, one RJ11 to RJ45 network cable 6 inches/15.3cm, providing a stable and reliable connection and avoiding signal loss.
- Reliable Materials: This ethernet to phone line adapter features a PVC outer sheath and PP insulation for the inner wires, with gold-plated metal contacts to ensure good connection and sound quality.
- Easy to Use: The RJ11 to RJ45 adapter uses a convenient snap-on clip to ensure a secure connection, corrosion resistance, and reliable performance. No telephone line wall socket required, nor is it necessary to modify an Ethernet wall socket.
- Main uses: Connecting fixed devices such as telephones, fax machines, and DSL modems via Ethernet cables. This adapter is ideal for extending Ethernet cabling in homes, offices, schools, hotels, and other locations.
- Important Note: It is not compatible with Wi-Fi connections.This product is not intended for transmitting router broadband data over telephone lines unless your landline service is accessed through the router's telephone jack.
| Model | Documented ports | Possible use |
|---|---|---|
| Cisco ATA 191 | Two FXS ports and Ethernet | Connects analog phones to a supported IP telephony system. Confirm the intended call-control platform and provisioning requirements in the Cisco data sheet. |
| Grandstream HT813 | One FXS port and one FXO port | Combines a phone-facing analog connection with a line-facing connection for a traditional phone line. See the Grandstream HT813 FAQ. |
What to verify before connecting it
- Use the FXS port for the analog handset and the FXO port for a traditional line; plugging into the wrong interface will not provide the intended connection.
- Confirm the adapter is configured and accepted by the VoIP provider or call-control system. Models are not automatically compatible with every service.
- Check that any specialized analog device and the features it needs are supported by both the ATA and the service.
Product prices and availability are accurate as of the date/time indicated and are subject to change. Any price and availability information displayed on Amazon at the time of purchase will apply.
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