Why is there no ringback tone when calling into 3CX via a Sangoma PRI card?

This is because the Sangoma NetBorder software is configured for the PSTN side to provide the ringing, so if it is not then you will not hear any ringing. To fix this issue we must tell Sangoma NetBorder Express to provide the ring back tone. To do this, follow the steps below.

  1. First go into the “Gateway Manager” web interface and then click on “Configuration / PSTN Config”.
  2. Next go to “Call Control” > “ISDN configurations” and then select your T1 configuration.
  3. Next in the configuration change the “Inband Progress Tones Generation:” as shown below to “ALWAYS”.
  4. Stop and start the gateway to apply the changes.

The “Inband Progress Tones Generation” field can have 1 of 3 values:

  1. “never” – the gateway does not generate tones.
  2. “as-needed” – the gateway rings if it receives a 180 and the call is not end-to-end ISDN (information element in the incoming ISDN SETUP message).
  3. “always” – the gateway generates a ring tone when it receives a 180, regardless of the content of the ISDN SETUP message.

By default, the gateway uses the “as-needed” setting. To force the gateway to ring, you should use “always”.

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