Some Emergency Service provider's phone systems do not send the Connect message to establish the call fully end to end, even after the operator answers the call. If the call originates from a SIP device or a Lync client it will result in one way audio. This Best Practice describes how to configure the Sonus
SBC 1000/2000 to force the originating device to open the voice path in both directions in situations where the Connect message is not received from the terminating carrier.
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The instructions below assume you are logged into the WebUI and connected to the applicable Sonus SBC 1000/2000. |
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This example applies to Sonus SBC 2000 system logs; the same process applies to obtaining Sonus SBC 1000 system logs. |
- From the WebUI, access Logs. See Working with Logging.
- Ensure the log level is set to Trace (see Managing Subsystems Logging).
- For CAS: Set to CAS TRACE level.
- For ISDN: Set to ISDN TRACE level.
- View the logs. The connect message data (noted in the red lines below) should be present in the logs for 911 calls. These messages indicate the PSTN is sending the connect message to the SBC. If these lines are not present, you must configure the SBC for emergency services.
- Configure the SBC for Emergency Services.
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| 0 | Figure |
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| 1 | Verify Connect Message through Logs - For SBC 2000 |
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| This example is a Trace Level System log, which applies to Sonus SBC 2000 with CAS E&M Signaling. 
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