Analog Telephone Adapter (ATA) Comparison and User Manuals

Phone Adaptor Overview

Assuming high speed internet already exists, a VoIP phone adapter or ATA (Analog Telephone Adapter) is the only additional item of equipment that is required to enable VoIP service in your home or small business with your existing analog telephones. This adapter is required to convert analog phone signals into digital signals (IP packets) and allows your phone calls to use VoIP and be transmitted and received over the Internet. An ATA is however not required if you decide to use IP enabled telephones as these phones already transmit and receive digital packets, and can be directly connected to your network via an Ethernet cable. For the purposes of this discussion, we will assume that you want to use regular analog phones. This includes DECT devices as although DECT stands for Digital Enhanced Cordless Telecommunications, they still use analog signals for phone calls.

Selecting the Right Adapter

As mentioned above, a phone adapter is a simple device that converts your analog telephone signals (your voice) into a digital format to send over the Internet. It also does the opposite in the receive direction, that is to convert a digital formatted incoming voice call into an analog stream to send to your existing analog phone. The following features should be considered during selection. Use this information in combination with our comparison table below to select the right device for your needs:

• FXS Ports: These ports allow you to connect devices such as analog phones. If you will need to connect two phones then look for a device that has 2 of these ports. Many home scenarios will have a single base telephone with satellite phones that wirelessly connect to the main base phone. If this is the case for you then you will only need 1 FXS port.
• FXO Ports: This port allows you to connect a POTS (Plain Old Telephone System) phone line to your adapter. You will most likely want one of these ports if you plan on keeping a landline for emergency or other situations.
• VoIP Protocols: There have been various protocols used for VoIP over the past few years, such as SIP (Session Initiation Protocol), SCCP (Skinny Client Control Protocol), MGCP and H.323. However, the most common is SIP which is a standards-based protocol. Just make sure that your selection is compatible with your chosen service provider. For more in-depth information check our our articles on Protocols and SIP.
• Codecs: When an ATA transforms analog phone signals into a digital format and vice versa there is some compression/decompression respectively that occurs. This can be important if you have limited Internet bandwidth (speed) as some codecs create "smaller" digital packets that need less bandwidth for transmission. It can also allow you to experiment with different codecs to see which produces the best quality sound for your system. Again, be careful to make sure the codecs supported by the device chosen match those supported by your service provider. Our Call Quality article provides a good overview of the most commonly used codecs.
• Ethernet Ports: At least one Ethernet port will be included for connecting the device to the Internet. Some older devices may only support the 10Mbps standard but typically this is not something the home owner need worry about. If you dont have a router of some sort then two (2) ports will be the best choice. This is also a good choice as allows you to place your ATA upstream of your computer devices. If you have a router with spare ports then only one Ethernet port is required.
• Quality of Service (QoS): QoS provides a way to prioritize voice traffic on your network over data. This can be important if your data needs can spike and phone quality is important at all times (i.e. higher usage). Some devices have this feature. This may not be required if you have other devices in your network, such as some routers/modems, that have this capability.
• WiFi: Some available wireless routers also include the ATA capability. You still need to connect your existing analog phone to the router using a cable so it is not a true wireless setup. If you dont have easy access for your phone to connect to your Internet modem though, this can be a neat solution.

Free Lease Option

When signing up for a VoIP phone service, it is easy to select what is typically a free phone adapter lease option, and let the provider send you one of their choosing. This can be a great option but there are some things to consider:

• Leased units are preferred models as providers have tested them thoroughly (in most cases).
• You often do not have a choice of which type of ATA that is sent to you. This can cause some issues depending upon your Setup.
• There are often shipping charges in addition to charges related to cancelation or replacing a broken device.
• As providing the unit is an additional cost for the provider, and they are selling a low cost service, it is unlikely that the free lease unit will be the latest and greatest.
• Bring Your Own Device (BYOD) is actually a fairly cheap alternative. Just double check that the provider supports it before buying one.

If you review our troubleshooting section, you will see that the majority of problems that people run into are related to either call quality or setup and configuration. So if you do select the free lease option, the bottom line is that you need to pay attention to which model you are going to receive from the provider.

• Decide if a free phone adapter lease or BYOD is right for you.
• Looking for ATA configuration guides? Review our selection of user manuals in the comparison table below.
• Need to upgrade ATA firmware? Skip to our firmware section below.
• Want to know what the hidden costs are of free ATA leases? Skip to the service provider information section.

Please use our comments box at the end of this page to let us know your experiences with any of these models and also let us know if you would like to see additional ones added to this list.

Analog Telephone Adapter Comparison Tables

Below you will find comparison tables broken into manufacturer groupings.

Cisco/Linksys/Sipura ATA's

Model	Image	Price *	Available **	10 Mbps	10/100 Mbps	FXS Ports	FXO Ports	Router	QoS	WiFi	Manuals
SPA112		$45.00		0	1	2	0		802.1p		SPA112
SPA122		$70.00		0	2	2	0		802.1p Diffserv ToS		SPA122
PAP2T		$69.00		0	1	2	0		Diffserv ToS		PAP2T
SPA2102		$75.00		0	2	2	0		Diffserv ToS		SPA2102
SPA3102		$70.00		0	1	1	1		Diffserv ToS		SPA3102
SPA8000		$210.00		0	1	8	0		802.1p Diffserv ToS		SPA8000
SPA8800		$425.00		0	1	4	4		802.1p Diffserv ToS		SPA8800
RT31P2		$55.00		0	4	2	0				RT31P2
RTP300		$50.00		0	5	2	0				RTP300
WRT54GP2		N/A		0	4	2	0			802.11b/g	WRT54GP2
WRT54GP2A		N/A		0	5	2	0			802.11b/g	WRT54GP2A
WRP400		$95.00		0	4	2	0		802.1p Diffserv ToS	802.11b/g	WRP400
SPA1000		N/A		1	0	1	0				SPA1000
SPA1001		N/A		1	0	2	0				SPA1001
SPA2000		N/A		1	0	2	0				SPA2000
SPA2002		N/A		1	0	2	0		Diffserv ToS		SPA2002
SPA2100		N/A		2	0	2	0		802.1p Diffserv ToS		SPA2100
SPA3000		N/A		1	0	1	1		Diffserv ToS		SPA3000
PAP2v1/v2		N/A		0	1	2	0				PAP2v1/v2

* The pricing listed above is estimated based on price listing on ecommerce sites offering these products.

** An ATA marked with an X in the "still for sale" column above has a manufacturer End of Life (EOL) notice and is also likely End Of Support (EOS)

Grandstream ATA's

Model	Image	Price *	Available **	10 Mbps	10/100 Mbps	FXS Ports	FXO Ports	Router	QoS	WiFi	Manuals
HT502		$45.00		0	2	2	0		802.1p/q Diffserv ToS		HT502
HT503		$60.00		0	2	1	1		802.1p/q Diffserv ToS		HT503
HT701		$35.00		0	1	1	0		802.1p/q Diffserv ToS		HT701
HT702		$40.00		0	1	2	0		802.1p/q Diffserv ToS		HT702
HT704		$100.00		0	1	4	0		802.1p/q Diffserv ToS		HT704
GXW4004		$100.00		0	2	4	0		802.1p/q Diffserv ToS		GXW4004
GXW4008		$167.00		0	2	8	0		802.1p/q Diffserv ToS		GXW4008
HT286		N/A		1	0	1	0		802.1p/q Diffserv ToS		HT286
HT386		N/A		1	0	2	0		802.1p/q Diffserv ToS		HT386
HT486		N/A		2	0	1	0		802.1p/q Diffserv ToS		HT486
HT496		N/A		2	0	2	0		802.1p/q Diffserv ToS		HT496

* The pricing listed above is estimated based on price listing on ecommerce sites offering these products.

** An ATA marked with an X in the "still for sale" column above has a manufacturer End of Life (EOL) notice and is also likely End Of Support (EOS)

Obihai ATA's

Model	Image	Price *	Available **	10 Mbps	10/100 Mbps	FXS Ports	FXO Ports	Router	QoS	WiFi	Manuals
OBi100		$39.99		0	1	1	0		802.1p Diffserv ToS		OBi User Manual
OBi110		$49.99		0	1	1	1		802.1p Diffserv ToS		OBi User Manual
OBi200		$59.99		0	1	1	0		802.1p Diffserv ToS	With OBiWiFi on USB port	OBi User Manual
OBi202		$74.99		0	2	2	0		802.1p Diffserv ToS	With OBiWiFi on USB port	OBi User Manual

* The pricing listed above is estimated based on price listing on ecommerce sites offering these products.

** An ATA marked with an X in the "still for sale" column above has a manufacturer End of Life (EOL) notice and is also likely End Of Support (EOS)

Phone Adapter Firmware

If you need to upgrade the firmware in your phone adapter, please use the following information to direct you to the correct manufacturers firmware section:

Manufacturer	Firmware Location
Cisco	Cisco Firmware Revisions
Linksys	Linksys Firmware Revisions
Grandstream	Grandstream Firmware Revisions
OBi	OBi Firmware Revisions

Service Provider ATA Information

As mentioned, there are some hidden costs related to free lease ATA's that everyone should be aware of before choosing that option.

Provider	Free Lease	S&H Fee	Replace Fee	Options	Models
		$12.95	N/A	N/A
		$0.00	$49.95	Linksys (PAP2T, RT31P2 Grandstream (HT502, HT701)
		N/A	N/A	OBi
		$14.95	$39.99	N/A

The details in the above tables were taken from a combination of manufacturer and provider websites.

Related Articles for Further Reading:

• Top 10 Best Routers for VoIP

---

WhichVoIP Visitor Comments

#4 : Posted by Kent

I'm trying to find an ATA to run an auto dialer for temperature sensor alarms. I'm on a VOIP PBX system at the location required. would prefer the ATA to set up as an H.323 endpoint.

-> Response: Any particular reason you need H.323? Asking simply because very few adapters support this standard these days. Audiocodes may have some that still support it but Grandstream and the likes no longer seem to support it.
Also, you may be better looking at some Internet of Things (IoT) type modules for this type of project i.e. one that is purely connected to the Internet and allows you to write a small program to send temperature sensor info to the Ethernet interface. Just a thought.

 

#3 : Posted by Sue

My internet provider will not allow me to purchase a wired modem with both an ethernet port and a LAN port (or USB or telephone port). I do not prefer wifi. How can I connect an ATA to a modem with only one Ethernet port?

-> Response: You need an Ethernet switch. You would then connect your Internet provider's box to the switch and then have multiple wired ports on the switch that you could connect the ATA (and other devices) to.

 

#2 : Posted by Asif Ul Alam

Can you please tell me which ATA converter supports the SCCP protocol?

-> Response: There are very few ATAs that seem to support SCCP. If you really must use SCCP, try the Cisco ATA186 or 188. They can be configured to support SCCP but are expensive. However you may be able to pick a used one up on Amazon for around $40.

 

#1 : Posted by Steve

I used the Cisco SPA112 and it saved me so much money. I had an analog phone so I thought I would not be able to use it anymore by transferring to VoIP, but this little ATA saved everything.