No ringback tone dialing from 3CX Phone system to PSTN line

[xylogistix]

Good Day Ladies & Gents

I have a problem getting my Grandstream FXO to work with the 3CX Phone System Version 10
Please see attached JPEG file for my setup diagram.

The Problem is,
When I dial a PSTN number from an extension on a 3CX Phone system, I cannot a ringback tone or hear anyting from the otherside.
The PSTN phone rings but I cannot hear it and when it is answered, they can hear but I cannot hear them.

When a call comes through from the PSTN line to the 3CX phone system, a ringback tone is audible and the designated extension to recieve call rings. When I answer, agnain I cannot hear anything but the call can hear me.

I am using 3CX Phone System version
Extension to Extension calls are OK
The FXO Voip Router is Grandstream GWX4101
I am located in Zambia

Were can I look for fix this problem?

regards

Chris (Xylogistix)

 

[leejor]

Re: No ringback tone dialing from 3CX Phone system to PSTN l

Is there a reason that the gateway is not located on the same network as the server or other devices? It should work, but that is not the "normal" sort of set-up.

Have you run the 3CX firewall tester. As it is the 3CX sets not hearing audio, I would suspect that the issue is in the router/firewall at the 3CX end. Some ports not forwarded properly?

I'm assuming that the Gateway, being on a public IP, has no firewall /NAT device in front of it.

You should not be posting the full public IP address of any devices, on the forum.

 

[lneblett]

Re: No ringback tone dialing from 3CX Phone system to PSTN l

Chris -

Thanks for starting the new thread, but in your last post in the old thread you stated something external. Now I am confused. As Leejor suggested, the configuration you seemingly have is not what most will expect. While he was responding to your post, I was putting together a quick diagram of what I think your configuration should look like. Please see the attached.

Leejor and I both agree that the GXW would be better served if on the same intranet as the rest of your system. If this is not possible for some reason, then the issue is apparently a firewall where port forwarding is established correctly. I also added the external extensions in the drawing in the event that the real issue is with these phones rather than extensions that are internal.

So, can you confirm which devices are external - phones or GXW.

 

[xylogistix]

Re: No ringback tone dialing from 3CX Phone system to PSTN l

Good Day
The 3CX phone system is in remote location.
It is connected to the internet via a wireless link.
The quality of the internet at this remote site is very good, but they have no phyiscal to access to PSTN lines (i.e. no PSTN cables to the site). This is how we came up with the idea of accessing the PSTN lines via the internet.

The IP addresses I have used in the drawing are not real
The port fowarder on the router are as follow

Port range 5000 - 6000 UDP/TCP points to 192.168.80.190 (3CX Phone system server)
Port range 9000 -9050 UDP/TCP point to 192.168.80.190
Port range 7000 - 7500 UDP /TCP points to 192.168.80.190

I am using a linksys router WRT54GL

The setup is in port range forwading of the applications & gaming menu.

Regards

 

[lneblett]

Re: No ringback tone dialing from 3CX Phone system to PSTN l

The issue appears to be related to how the gxw is set related to its physical location. The template configuration I had you set considered the gxw to be located on your LAN and not in the public IP realm. As a result some settings may need to be changed. you keep failing to provide the full details of your implementation as we only find out now about it being a wireless connection for Internet service. This now makes me wonder if the access point and client are operating in bridge mode, wireless router, etc. and if they might impact how streams flow. What make and model are the radios? In what mode are they operating?

At your router, ensure that sip-alg is disabled. You should also have a fixed IP.
I had other suggestions, but with this new information, they may no longer be applicable.

 

[xylogistix]

Re: No ringback tone dialing from 3CX Phone system to PSTN l

The radios are Nano Station 5 fives operating in bridge mode.
At the moment I have setup a similation in my offices using UTP cable and I getting the same problem.

 

[xylogistix]

Re: No ringback tone dialing from 3CX Phone system to PSTN l

Yes .. all IP address are fixed.
Another thing I have tried is seting a remote extension using 3CX tunnel or 3CX proxy Tunnel... I am able to make calls in out of the 3CX phone system server.

 

[xylogistix]

Re: No ringback tone dialing from 3CX Phone system to PSTN l

I have also run firewall checker from the 3CX phone system.
All looks fine, only the STUN is unreachable, but this cannot be the issues.

 

[lneblett]

Re: No ringback tone dialing from 3CX Phone system to PSTN l

OK, The NANO is a good product and should be transparent to the streams.

I am not certain what is meant by setting up the tunnel and being able to make calls in an out of the 3CX server. Does this mean that you using the remote extension you can make a call to an internal extension and that an internal extension can make a call to a remote extension? Does this mean that the remote extension can make and receive calls through the GXW?

If you continue with the network as I now understand it, it will likely require some changes to ports and settings on the GXW. Before we go down that path, you might want to consider the attached drawing. This illustrates a dedicated wireless path to where ever you want the GXW, but keeps it inside your LAN. Yes, it does mean an extra set of NANOs, but this may be cheaper and more effective in the long run as it does not co-mingle web and voice on your one internet connection.

 

[xylogistix]

Re: No ringback tone dialing from 3CX Phone system to PSTN l

The remote extension are not going through the GWX but direct through the public IP of the 3CX phone system server. I am using the 3CX soft phone.

The diagram that you have provided would have been the idea solution but there are PSTN lines any near the wireless access point.
The access point is only providing access to the internet. The PSTN lines are miles away from the access point.

Regards

 

[ZenMasta]

Re: No ringback tone dialing from 3CX Phone system to PSTN l

If it's helpful, I attached screengrabs of my gxw4104.

I had this successfully working when it was on the same lan as 3cx server. I know someone else shared sent you a config, but mine wasn't auto provisioned so maybe you can compare.

 

[lneblett]

Re: No ringback tone dialing from 3CX Phone system to PSTN l

I am not trying to show physical location, but logical. Remote extensions are not going thru the GXW and have nothing to do with the GXW. I do show the remote extension using the internet and public IP. It makes no difference if hard phone or softphone.

The GXW can be anywhere you want it to be. If you want the device to sit physically next to the ISP modem at the rmote location that is fine. I am merely illustrating that if you can set the GXW up with a second set of NANO radios, then you can avoid the routing issues and all. It becomes a point-to-point connection independent of the internet connection and all remains logically within your LAN, which is illustrated by the yellow shaded box.

The internet uses one set of radios, the GXW connects to the other set of radios via its WAN port. From a physical location perspective, move the GXW and the NANO, to which it is connected, to the same location as your internet and its NANO radio. You then have two paths, one for internet, one for voice and they are not co-mingled and the GXW need not traverse the NAT imposed by the router; hence it is and remains a part of the LAN subnet.

I am now showing the same drawing but taking into account the physical location as well. The yellow represents your logical LAN, the green the remote location where your Internet, ISP, NANO and now the GXW are located and the yellwo/green the overlapping that occurs between your physical and logical devices and then the red that shows the remote extension using a softphone.

If you are going to now tell me that the GXW and PSTN terminations are at a different location than where your ISP and modem terminate (as I have shown in green, then I am afraid that I will have to give up on this one unless you can provide a highly detailed drawing showing ALL elements that come into play at each location.

As I indicatd earlier, I was not awre that the device was remote, so the SIP server address is likely not valid given that it should be pointing to your static IP and then port forwarded. My drawing on this post allow the settings.

 

[xylogistix]

Re: No ringback tone dialing from 3CX Phone system to PSTN l

Good Day

what I mean by remote is as follows

The 3CX server is located on the farms.
The wiresless access point is within the farming area and reachable by Nono radion
The PSTN line are in another town about 50 miles from the farms and only reacheable via the internet.
The setup that you have demostrated in the drawing will work perfectly ok, but we cannot access the PSTN line due to geographic reasons.

 

[xylogistix]

Re: No ringback tone dialing from 3CX Phone system to PSTN l

Please see my GWX4101 config

 

[xylogistix]

Re: No ringback tone dialing from 3CX Phone system to PSTN l

hello

I have swapped the hand set with a diferent one.
Now I can get the ring back tone.
Now the problem is, the phone continiously ring even if the CALLEE (user on the other end) has picked up the handset to answer until the call times out.

 

[lneblett]

Re: No ringback tone dialing from 3CX Phone system to PSTN l

Sorry, but I can no longer help on this particular thread without your providing a specific drawing. I think there is confusion between how logical and physical is being interpret as I clearly show the GXW being in an entirely different physical location outside the farm. I show the GXW to be where your internet is, but instead of trying to piggyback the voice onto the internet wireless signal,I have the voice going across a different pair of radios so as to keep the GXW in teh same subnet and avoid port forwarding issues.

If you want to try and remote as I think you have it set, and insist on carrying intemixed with your internet data, then open ports 5000-10000 on the linksys router and forward all to the 3CX system.

 

[RichardCrabb1]

Re: No ringback tone dialing from 3CX Phone system to PSTN l

Hi,
I hope firstly that I understand the nature of the problem. I can see two ways to fix this issues-

1 Use a router with VPN to link 3CX to location of PSTN gateway. Routers at both sites would have to be something like a Draytek 2830. The quality of voice may not be very good, unless the Internet connection is suitable. This would allow you to point the GXW to the internal IP address of the 3CX. No network translation is needed so it would work. This is the simplest option to make work.

2) Make sure that the ports for RDP and SIP match the port forwarding of the router. For example, the RDP ports of the GXW could be set to 9000 to 9049. This is the same that 3CX uses as default. The GXW must point to the public IP address of the router. Obviously unless this is a static IP address this will not work. Similarly, the router that connects the PSTN gateway also needs NAT - unless you can connect it using a public static IP address. If the PSTN gateway has a private IP address, then ports need to be mapped through that router as well. The problem now is that we might be expecting too much for this to work without good knowledge!

3) One more method is to ensure that both 3CX and the GXW are connected directly to public IP addresses. This means that the ISP needs to allocate a range of IP addresses to each site. The 3CX computer needs firewall to be properly enabled. With Windows 7 3CX installs correctly enabling ports for 3CX - as long as the NIC with public IP is installed on the computer at the time of the install.

Both solutions really need static IP addresses for both sites.
Does that help?

 

[xylogistix]

Re: No ringback tone dialing from 3CX Phone system to PSTN l

Thanx Richard

The VPN solution sound like it can work.
I will feedback as soon as I run the tests.

Regards

 

[xylogistix]

Re: No ringback tone dialing from 3CX Phone system to PSTN l

Good Day

Sorry for the late renspose. This is due to serious medical issues.
I have tried the VPV solution has suggested by Richard and it works perfectly well. I have setup a VPN link between the two network and I can now recieve and make call via the FX0 plungged into the internet.

Thanx