3CX Phone System

The 3CX Phone System check monitors a 3CX V20 system through the official Configuration API. It runs every 5 minutes by default and checks system health, licence, TLS certificate, backups, updates, and call capacity.

Prerequisites

• A 3CX API integration with 3CX Configuration API access. If you exclude extensions from the registration warning, the integration also needs access to Users.
• A device that can reach the 3CX system over HTTPS.

Steps

1. In 3CX, create an integration under Admin > Integrations > API with 3CX Configuration API access. Copy the key shown once.
2. Add the 3CX Phone System check to a device that can reach the 3CX system over HTTPS.
3. Enter the FQDN or IP address without scheme or port under 3CX host. HTTPS port defaults to 443; older or customised installations may use 5001.
4. Enter the API client ID and API key, then save.

For assignment and required permissions, see Assign checks with config packages.

Settings

Every threshold also triggers on equality: licence and certificate once the remaining days reach or fall below the value, backup age and call capacity once they reach it. If you enter the warning and critical values the wrong way round, the check swaps them before evaluating.

Adjust extension warnings

If some extensions are deliberately unregistered, you can exclude their registration warnings without relaxing monitoring for the rest of the system.

1. Leave Warn about unregistered extensions enabled. It is on by default.
2. Enter the exact numbers under Ignored extension numbers, for example 0100 and 200. Leading zeros matter: 100 is not the same extension as 0100. The list is empty by default.
3. Make sure the 3CX API integration has access to Users. The check needs this additional access when you use exclusions.

To turn off all unregistered-extension warnings, disable Warn about unregistered extensions. Both settings affect only this warning. Displayed totals and other checks, such as trunks, phones, and services, remain unchanged.

If the check reports a permission error after you add exclusions, check API access to Users. A failed query is reported as a failure; the check does not treat it as a successful exclusion.

Results

A successful result means all enabled tests report no problem. Warning and critical results identify issues such as unregistered trunks or extensions, stopped services, missing or old backups, an inactive licence, or exhausted call capacity. A check failure instead points to authentication, permissions, reachability, or timeout.