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New ATA recomendation

PostPosted: 06/09/2021
by darekj
I am looking to buy a new ATA for my line. Can you please recommend which one to buy for the home use?
I had Linksys SPA112, but it broke, and I need a replacement.

Thank you and regards,
Darek Jagodzinski

Re: New ATA recomendation

PostPosted: 06/09/2021
by bridonca
This is one of the better ATA devices. ... B07FCS1NGM Very forgiving to set up

Re: New ATA recomendation

PostPosted: 06/09/2021
by hanke
That's a pretty good price!

Re: New ATA recomendation

PostPosted: 06/10/2021
by darekj
Hello all, thank you for your recommendations!
I just received this one today: Grandstream GS-HT802 --> Is this one going to work with FPL?

Darek J.

Re: New ATA recomendation

PostPosted: 06/10/2021
by Liptonbrisk
darekj wrote:I had Linksys SPA112, but it broke

Is it a power supply issue? Did you try another power supply that's rated for that ATA?

I just received this one today: Grandstream GS-HT802 --> Is this one going to work with FPL?

Yes, it will, but it's not as powerful as an OBi2xx series ATA that was suggested previously. If you're interested in looking for one, visit this post: viewtopic.php?f=15&t=18805#p76546.

If you wish to continue instead with the HT802, follow the steps below carefully in the order presented:

1) What brand and model modem are you using?

If you're using a modem/router combo, gateway, or hub issued by your ISP, contact your ISP to ask for assistance for disabling SIP ALG in it
If you are also using your own router in addition to the one supplied by your ISP, then you should be enabling bridge mode instead in the modem/router combo, gateway, or hub issued by your ISP.

2) What brand and model router are you using?
a) Make sure whatever modem/router combo, gateway, or hub your ISP gave you is in bridge mode if (and only if) you are using your own router as well. Call/contact your ISP if you have to.
For Bell Hubs, visit ... r-1993629/. For Rogers, visit ... ridgemodem.

3) Make sure you disable SIP ALG if you're using own router. Here is an example: If you wish for more specific help for disabling SIP ALG, I need the brand and model of the router you're using.

To understand why SIP ALG often causes horrible problems, please visit (scroll down to the section on SIP ALG problems).

4) I suggest following the settings listed in in this PDF guide as much as possible: viewtopic.php?f=15&t=18839
Particularly, ensure SIP REGISTER Contact Header Uses is set to WAN address.

Obviously, only use the firmware for your own specific ATA model. Grandstream ATA firmware is located at
Check for a firmware update.

5) This is always proper device reboot order:

A.Turn off modem, router and ATA.

B. Turn on modem. Wait for modem to be fully up and running.

C.Turn on router.
Wait for modem to be fully up and transmitting data before turning on router.

D. Turn on ATA only after the router is fully up and running.

Reboot your devices now.

6) Test with incoming calls. Getting incoming calls to work properly is often more problematic than making outgoing calls.

7) If incoming calls don't work, try for Primary SIP server in your ATA. The purpose of is to circumvent SIP ALG features, which monitors traffic on UDP 5060, in routers and mangles SIP headers.

Re: New ATA recomendation

PostPosted: 06/10/2021
by Liptonbrisk
And if you're interested, the following is information I wish I knew before starting out, especially point D.

(Generic info)

Typically, for VoIP SIP services, especially for Freephoneline/Fongo, you want

A) a router that does not have a full cone NAT,

Visit ... -punching/.
Mango from the forums writes,
“Use a restricted cone NAT router, and do not use port forwarding or DMZ. Restricted cone NAT will only permit
inbound traffic from the service provider you're registered to. If you have a full cone NAT router, it will allow traffic
from any source. This is probably not what you intend.
If you have a Windows computer, you can test your router using the utility here:,22292023. To run it, use stun from a command prompt.”
Essentially, you download the file; extract the stun.exe file from within the zip file to an easily
accessible location; use an elevated command prompt (visit ... inistrator); change directory (cd) to the
directory or location where you extracted stun.exe (visit ... c-commands); and type “stun” without
the quotation marks followed by the enter/return button on your keyboard.
Asus routers, at the time of this writing, produce port restricted cone NAT routers, for example and are fine,
provided you’re using one with Asuswrt-Merlin, third party firmware installed.

B) a router that lets you disable SIP ALG if it's buggy,

To understand why SIP ALG often causes horrible problems, please visit (scroll down to the section on SIP ALG problems).

If you're dealing with a modem/router combo issued by an ISP or a router with SIP ALG forced on, you may have
to use for the Proxy Server. The purpose of is to circumvent
faulty SIP ALG features in routers.

C) a router that allows you to set QoS or assign highest priority to your ATA or IP Phone over all other devices on your LAN (local area network),

For a very general description of what QoS can do for you, visit
The basic idea is if you're torrenting or have a bunch of other computers, smartphones, tablets, etc. downloading and uploading (hogging all your available bandwidth), you don't want
your ATA not to have access to enough bandwidth to make or receive calls properly. So QoS or a Bandwidth Monitor feature (which is just another form of QoS) is a really good idea for VoIP users.

I often get an occasional relative complaining to me, "Hey my calls sound choppy." And then when I go visit, some kids are playing MMOs on a computer, while another person is downloading a huge file,
and another person is backing up files to a cloud service all at the same time someone else is trying to talk on the phone. All those devices, without QoS enabled, are fighting over available bandwidth along with the ATA.

and D) A router that lets you adjust both Unreplied and Assured UDP timeouts.

Thanks to Mango, many of us now understand that in order for ATAs to remain registered and working properly with a VoIP SIP provider like Freephoneline, in particular after power failures, the following conditions must be met:

UDP Unreplied Timeout (in your router) < NAT Keep-alive Interval (in your ATA; for Obihai ATAs this is X_KeepAliveExpires; for Grandstream, the setting is SIP OPTIONS Keep Alive Interval) < UDP Assured Timeout (in your router) < SIP Registration Failure Retry Wait Time (or RegisterRetryInterval in Obihai ATAs)

“<“ means less than.

When a modem leases a new IP address, a problem can arise where prior associations using the old IP address are maintained in the router. When the ATA attempts to communicate using the old IP address, the response is unreplied, and then if the UDP Unreplied timeout is greater than the Keep Alive Interval (and UDP Unreplied timeout is often set to 30 by default in consumer routers) a problem arises where the corrupted connection persists. If UDP Unreplied timeout is, for example, 15, and the NAT Keep Alive Interval is 20, then the corrupted connection will timeout or close. A new connection will be created, and everything will work fine.

Another problem can occur when the Keep-Alive interval is greater than UDP Assured Timeout (often 180 by default in consumer routers): the NAT hole will close due to the ATA not communicating frequently enough with the SIP server. In turn, incoming calls may, intermittently, not reach the ATA. Again, X_Keepalives expires is supposed to be 20 with FPL.

(the above settings are making reference to those in Obihai ATAs)

Getting access to both UDP Unreplied Timeout and UDP Assured Timeout settings in consumer routers may be difficult, if not impossible. Asuswrt-Merlin (I would avoid any model below/less powerful than an RT-AC68U), third party firmware for Asus routers, does offer easy access to these two settings, which are found under General–>Tools-->Other settings. My understanding is that third party Tomato firmware has these two settings as well. So if your router supports Tomato firmware, that may be another option. Note that I will not be held accountable any damage resulting from failed firmware updates. Apparently, Mikrotik routers also allow users to change both Assured and Unreplied UDP timeout settings as well: ... #p28059363.

Router firmware that allows users to adjust Assured and Unreplied UDP timeouts include


The keep alive interval for FPL is 20. The SIP Registration Failure Retry Wait Time is 120. I use 15 for UDP Unreplied Timeout and 115 for UDP Assured Timeout.

ISPs do not issue customers routers that can do all four things I just listed. Typically it's far better to have your own router with strong QoS functions and a restricted cone NAT firewall,
disable whatever SIP ALG feature is enabled in the router, and stick whatever modem/router combo your ISP gives you into bridge mode. For Bell Hubs, visit ... r-1993629/. For Rogers, visit ... ridgemodem.