Announcement -


[06/11/2019] Google Voice dialing is not working, duto recent changes of Google Voice web login. Receiving GV calls is fine.

The new Google Voice app now supports SIP calls, both receiving and dialing. It now supports G729 and no one-way audio issues (NAT) even behind VPN. So on your phones, you may simply use that. Just select "Prefer Wi-Fi and mobile data" under "Make and receive calls".

For your home phone, you may get a FreeUP SIM card for free 1000 calls and 1000 text per month. It uses AT&T network. Then you can install the Voice app on it to dial GV and the CID will be your GV #.

[06/08/2018] 1-909-390-0003 has come back to normal.

[07/08/2017] 1-909-390-0003 now have no echo, but 1-925-259-0082 works fine.

[06/16/2017] Fixed the issue that Google does not recogonize the GV dialing device and no more such email alerts.

[06/16/2017] Google made a change again and broke GV dialing. Now fixed.

[02/10/2017] The new Google Voice issue is addressed and GV dialing is now fully functional again.

[02/09/2017] Google Voice dialing stopped working due to recent changes from Google.

[07/23/2016] Google made some changes again recently and caused GV dialing failure in the past few days. The issue has now been addressed and everything is working fine.

[05/27/2016] Added a new feature that allows receiving calls from a GW to a different line, see the updated Tweaks page for how to use it.

[04/09/2016] Added the following SIP ports:

65060 (identical to 5060)

65061 (identical to 5061)

65062 (identical to 5062)

For example, if you used to use 5060, now you may also use 65060 instead. We can add pretty much any ports upon your request in case your ISP blocks the standard SIP ports 5060 and 5061.

[04/06/2016] Google Voice dialing is now working again.

Another good news: I'll add two-step auth support for GV.

[03/25/2016] Google Voice dialing is currently not working, due to a recent change Google made. Sorry about this.

[10/26/2015] Authorized SSL certificate is applied, no more security warning when register a new account or login to manage it.

It's more than a year since KoT VOIP was opened to public. It's been a rock solid service, no known issue, it simply works.

Thank you all!

[02/09/2014] We are making some changes. One of the changes is on the account management:

From now on please use "" to manage your account. You can no longer use: "".

[05/22/2014] Domain name has been changed from to You should update your bookmark and make the following changes to your devices and softphones:  =>  =>  =>  =>


[05/13/2014] RegistrationPeriod is now set by KoT to ensure reliability and battery saving. You no longer need to deal with this on your devices.

[05/11/2014] 4-digit test numbers (such as 9196 etc.) no longer work, please use this toll free number for test: 1 (800) 444-4444.

[05/11/2014] Because some people experienced unreliable calls and did not know how to set keepalive, I have added this function on the server side. From now on, if you use UDP which is by default on most ATA's and softphones, you no longer need to do anything about this issue to enjoy reliable calls.

As before, if you use a mobile device, you should use TCP without keepalive to save battery. But if you're behind a router that closes idle TCP sockets too soon, then you still need to use a proper keepalive interval or use UDP.

Either UDP or TCP, recommended value for "register expire" is 5 to 15 minutes (300 s to 900 s). Too short is not necessary and causes troubles; too long, on the other hand,  takes too long to recover from a network interrupt.


[05/09/2014] Ports 5061 and 5081 are added. They behave the same as 5062 and 5082 do. The reason for this is: Sipdroid does not allow 5062.


[05/06/2014] More codecs are now supported: PCMA,PCMU,G729,iLBC,GSM,speex,BV16.

To use these codecs, you must register your endpoints to port 5062 instead of 5060 and your Ipkall and Callcentric numbers must be forwarded to 5082 instead of 5080.

Before: or




(replace "11234567891" with your line number)

Use this option only if you're sure that you and your calling partners use the same codec.


[05/01/2014] Security enforcement. Register interval must be 5 minutes or longer, or your device/softphone may be banned for 10 minutes (600s). If you miss calls, use TCP instead of UDP and/or enable keepalive - set it to 30 to 115 seconds.