Grandstream FXO Gateway GXW410X Caller ID Detection with 3CX Phone System

3CX Grandstream Caller ID not detected


We’ve always seen issues using GXW4104/4108 for not identifying caller ID on the incoming call. Here are some steps you may want to go through during the troubleshooting.



1. Ensure you have CLI enabled on your phone line.
Make sure that the Caller Line Identification or CLI is enabled for the majority of phone landlines with your service provider. Many people are unaware that most telephone companies charge for the service.

2. Ensure you have CLI enabled on ALL the PSTN trunks that you plug into the GXW410X, even those that share the same number
If you have a phone line with one number but more than one trunk (or in other words, you have a number of lines terminating in different PSTN ports but they all share the same number), you have to enable CLI on each and every one of the trunks. That means sticking a normal analog line into each PSTN port. The reason for this is that although they may all share the same number, from a call routing perspective they are their own individual entities.

3. Your distance to the exchange will affect how many rings are required for the caller ID to be delivered
Your distance and line quality will affect how many rings are needed before the caller ID is delivered. Normally, 3 rings are acceptable and anything less than 3 will not work in any circumstances. If you do need more rings then just increment the Number of Rings before pickup by 1 until it works.

On GXW410X

4. Ensure your configuration settings are correct in the GXW410X.
For caller ID to work, the settings of the GXW410X must be very specifically set.

Recommendations (GXW4104):

Dial tone:ch1-4:f1=350@-11,f2=440@-11,c=0/0;

Ringback tone:ch1-4:f1=440@-11,f2=480@-11,c=200/400;

Busy tone:ch1-4:f1=400@-11,f2=400@-11,c=300/0;

Re-order tone:ch1-4:f1=400@-11,f2=400@-11,c=300/0;

AC Termination Impedance:ch1-4:4;
Enable current Disconnect: Y
Current Threshold: 5
The number of rings before pickup: ch1-4:3; **This parameter depends on your location.
Caller ID scheme: ch1-4:10 (toggle between the different values of “Caller ID scheme” )
Caller ID transport type: ch1-4:1;
RX Gain: Increase the value by +6dB or +12dB to reduce the noise

Min Delay Before Dialing Out:  ch1-4:1300;

Note:  This entry changes the amount of time that the GXW4104 will wait after picking up the phone and before dialing out.  If you have a delay before getting a dial tone, you may need to change it.

5. Disconnect any splitter or adapter on your PTSN line.

Integration with 3CX

If you are using GXW410X with 3CX, and you are getting an Unknown Caller ID, please:

a. perform an upgrade to internal build or

b. Set the number of Rings before pickup is set to 4 and the Caller ID Scheme to 2.

Upon the changes, if you are facing a gateway registration issue, make sure you create a Generic Gateway profile in 3CX.

Analysis by Audacity

Figure 1 CID detection analysis of Grandstream FXO Gateway GXW4104

The figure above shows that GXW4104 picks up the CID in the detection process. Notice how the noise masks the CID signal. The unusual ring-back cadence didn’t affect the CID detection because the CID was sent after the first ring pulse. The CID detection always starts after the first ring and has a length of ~ 3 seconds. The DSP failed to analyze the CID due to the noise.

Figure 2 shows that the noise in the PSTN line is too large and it covers the CID signal. 


Connecting GXW410X with 3CX User Guide

Configuring GXW410X Gateway with 3CX

Configuring GXW410X Gateway with FreePBX