FAQ - voip.kots.us


Google Voice dialing stopped working?

If you logged into your GV account recently, this might happen. You just need to do the captcha fix again:

Login to your GV account and then open this link in the same web browser:


Then make a call again right after.

Why not just use Sipdroid and pbxes?

Although Sipdroid is perfect (once with G729 added and bugs fixed), but pbxes.org is not. For Google Voice, you either use G711 that's not 3G friendly or use transcoding that always sucks. If you are behind NAT, proxy and/or VPN, you cannot bypass audio.

Let me repeat: relaying, proxying and/or transcoding voice are always very bad to VoIP and Vo3G. No need to mention privacy when your voice goes through a third-party server.

Simply put: if Sipdroid + pbxes works, why would I use SipSorcery instead? The first time I used pbxes was about 6 years ago and I still have several active pbxes accounts. So I know how pbxes is.

Why not use SipSorcery?

  • It cannot handle NAT issues well. I often got no audio after I pick up a call. This past holiday season was driving me crazy with so frequent one-way audio problems. This is the direct motivation for me to build KoT VoIP during the holidays.
  • Writing dialplan script in Ruby is too difficult for ordinary users.
  • Once a free service is now quite expensive at $75 per year.

What's the difference between paid and free accounts?

The free account has 10 lines reserved but only 1 of them is activated. It is enough for receiving and placing Google Voice calls and using your own service provider (gateway) for cheap international calling.

The paid account has all 10 lines activated, then you can do much more, such as free calling between these lines, using more GV and GW accounts, and beyond, see Tweaks for more details.

Switching back and forth between these two types of accounts is no hassle, everything you set up is always there, just not all activated when not paid.

Does KoT VoIP support 911?

No, KoT VoIP does not support 911 nor any kind of emergency call. And KoT VoIP does not bear any responsibility for your using its service.

In general, it is never a good idea to use 911 with VoIP.

Those said, KoT will pass 911 calls via GW (gateway). For example, if you dial 011911, 012911, ... or 019911, 911 will be sent to the GW defined in that line. Add <911:011911> (or <911:012911> etc.) in your ATA's dialplan.

Again, doing so is on your own risk!

My device/softphone can barely register to KoT

Set the register interval to at least 5 minutes. If this value is too short, the system may ban it as suspicious activities. If inbound calls are not reliable, use keepalive and set it to 30 - 115 seconds.

If you used wrong username/password and retried repeatedly too many times within a short period, your IP will be blocked for 10 minutes. Therefore, don't retry too quickly after failures; if you did, you may still fail in the next 10 minutes even after username/password are corrected. Once blocked, wait for 10 minutes before you try again.

If you have multiple endpoints from the same location/IP and any one of them tried too many times within a short period with a wrong username/password, the IP will be blocked and thus all the endpoints cannot register in the next 10 minutes. So, you must unplug any device, and exit any softphone, that has the wrong username/password; otherwise it will keep retrying and cause the IP and other endpoints being blocked.

I still cannot register my phone to KoT

Common mistakes are:

  • You use your master number as your username. Username is always 11 digits and never end with 0.
  • You use your KoT account name as username. Again, username is always 11 digits, starting with 123 or 1123.
  • You use your KoT account password as the password. After you logged into your KoT account, you see the password right below the line number.
  • You use port 5080 (or 5082, 5081). The correct port is 5060 (or 5062, 5061).
  • You enabled DNS SVR. Either disable it or register to kots.us instead of sip.kots.us.

Sometimes I cannot receive calls

You need to enable keepalive, usually 55 seconds is fine. Otherwise your router closes the connection between your phone and KoT, and neither of them are aware of the disconnection. Then, when a call comes in, your phone won't be able to receive it.

Keepalive will send small packets from your phone to KoT to keep the connection alive. Use TCP instead of UDP also helps a lot about this issue, allowing you to use a much longer keepalive interval or not use it at all.

Obi200 has a TCP bug, so use UDP instead and keepalive.

Some routers such as Xfinity will always close a live connection after several minutes, then keepalive cannot help and thus you must use a shorter register interval such as 5 or even 2 minutes.

Sometimes when I place a call but the other party never get a ring

See above topic for the cause and solution.

When your phone is disconnected by your router, neither your phone nor KoT are aware of the disconnection. When you place a GV call at such a moment, KoT will still place the call for you and send you the ring. However, when KoT forwards the call from GV back to your phone, it won't reach you, because the connection was already broken. As the call does not reach you, GV won't go to the next step to connect the call to the other party and thus it won't get a ring.

When I pick up a call, I always need to press 1

Log into your Google Voice account, Settings, Calls, turn off "Call Screening".

I forgot my KoT account password

You must email us for a password reset.

When I call 800-444-4444, the reported CID is wrong

This toll-free # is for very basic testing only, just to see if you are ready to move to the next step of the setup.  To avoid any unnecessary involvement, it simply uses a 3rd-party toll-free gateway and therefore shows its CID. As long as this call is successful - heard the female voice, ignore any other details and move on. Once you've set up other things, such as your own SIP gateway or GoogleVoice, then call your cell phone # to check your CID.

My ISP blocks the standard SIP ports 5060

You may use the following ports instead:

65060 (identical to 5060)

65062 (identical to 5062)

If you need to use other ports, let us know.