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

Description

Many users encounter issues with the GXW4104/4108 not identifying caller IDs on incoming calls. Below are some troubleshooting steps to help resolve these issues.


Troubleshooting Steps

Telco Provider

1. Enable Caller Line Identification (CLI)
Ensure that CLI is enabled on your phone line with your service provider. Many users are unaware that this service may incur additional charges.

2. Enable CLI on All PSTN Trunks
If you have multiple PSTN trunks sharing the same number, ensure CLI is enabled on each one. Each trunk acts as a separate entity, which requires individual CLI activation.

3. Consider Distance to the Exchange
Your distance from the exchange can affect the number of rings required for caller ID delivery. Typically, 3 rings are necessary; anything less may not work. If you need more rings, increment the “Number of Rings Before Pickup” by 1 until it operates correctly.

On GXW410X

4. Verify Configuration Settings
Ensure that the GXW410X settings are correctly configured for caller ID functionality. Recommended settings for the GXW4104 include:

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 // Adjust if necessary.

5. Disconnect Any Splitters or Adapters

  • Remove any splitters or adapters from your PSTN line, as they may interfere with signal quality.

Integration with 3CX

If you’re using the GXW410X with 3CX and encountering an “Unknown Caller ID,” consider the following:

a. Upgrade to internal build 1.4.1.8 or 1.3.4.13

b. Set the “Number of Rings Before Pickup” to 4 and change the “Caller ID Scheme” to 2.

If you experience gateway registration issues after these changes, create a Generic Gateway profile in 3CX.


Analysis by Audacity

Figure 1: CID Detection Analysis of Grandstream FXO Gateway GXW4104

The analysis shows that the GXW4104 successfully detects the CID during the call. However, noise can mask the CID signal. Notably, the unusual ring-back cadence did not hinder CID detection, as the CID was transmitted after the first ring pulse. CID detection begins after the first ring and lasts for approximately 3 seconds, but noise can impede accurate analysis.

Figure 2: The noise level in the PSTN line may be too high, covering the CID signal.

References

Connecting GXW410X with 3CX User Guide

Configuring GXW410X Gateway with 3CX

Configuring GXW410X Gateway with FreePBX