edit pass: quality-and-diagnostics

Author: ShawnJackson

articles/communication-services/concepts/telephony/troubleshooting-pstn-call-failures.md

@@ -1,6 +1,6 @@
 ---
-title: Troubleshooting PSTN call failures - Azure Communication Services
-description: How to troubleshoot PSTN call failures by logging and viewing call codes.
+title: Troubleshoot PSTN call failures - Azure Communication Services
+description: Learn how to troubleshoot PSTN call failures by logging and viewing call codes.
 services: azure-communication-services
 ms.date: 11/24/2023
 author: slpavkov
@@ -10,49 +10,44 @@ manager: aakanmu
 audience: ITPro
 ms.topic: troubleshooting
 ---
-# Troubleshooting Azure Communication Services PSTN call failures
+# Troubleshoot Azure Communication Services PSTN call failures
 
-When troubleshooting Azure Communication Services PSTN call failures, we recommended that you [enable logging](../analytics/enable-logging.md). Then you can use `ResultCategories`, `ParticipantEndReason`, and `ParticipantEndSubCode` values to determine why an individual call ended and whether the system detected any failures.
+When you're troubleshooting Azure Communication Services PSTN call failures, we recommended that you [enable logging](../analytics/enable-logging.md). Then you can use `ResultCategories`, `ParticipantEndReason`, and `ParticipantEndSubCode` values to determine why an individual call ended and whether the system detected any failures.
 
-## Using ResultCategories to troubleshoot PSTN call failures
+## Use ResultCategories to troubleshoot failures
 
-The `ResultCategories` array is a property of the [Call summary log schema](../analytics/logs/voice-and-video-logs.md#call-summary-log-schema) and contains a list of general reasons describing how the call ended.
+The `ResultCategories` array is a property of the [call summary log schema](../analytics/logs/voice-and-video-logs.md#call-summary-log-schema). It contains a list of general reasons that describe how the call ended:
 
-General reasons that a call ended:
+- `Success`
+- `Failure`
+- `UnexpectedClientError`
+- `UnexpectedServerError`
 
-- Success
-- Failure
-- UnexpectedClientError
-- UnexpectedServerError
+This information can help you determine why a call ended without generating a detailed error log.
 
-This information can help developers determine why a call ended without generating a detailed error log.
+## Use ParticipantEndReason and ParticipantEndSubCode to troubleshoot failures
 
-If this level of detail isn't sufficient, then developers can use `ParticipantEndReason` and `ParticipantEndSubCode` to understand the reasons for call end in greater detail. For more information, see the next section.
+If the level of detail in `ResultCategories` isn't sufficient when you're troubleshooting PSTN calls, you can use `ParticipantEndReason` and `ParticipantEndSubCode` to understand the reasons why a call ended in greater detail. `ParticipantEndReason` and `ParticipantEndSubCode` are also properties of the [call summary log schema](../analytics/logs/voice-and-video-logs.md#call-summary-log-schema).
 
-## Using ParticipantEndReason and ParticipantEndSubCode to troubleshoot PSTN call failures
+### ParticipantEndReason
 
-The `ParticipantEndReason` and `ParticipantEndSubCode` are properties of the [Call summary log schema](../analytics/logs/voice-and-video-logs.md#call-summary-log-schema) and provide more details about why the call ended.
+`ParticipantEndReason` is a three-digit code that shows the general call status. This code explains why the call ended and groups failures by category. For example, `ParticipantEndReason 404` means that caller or callee wasn't found. `ParticipantEndReason 500` means that a service error occurred.
 
-When you're troubleshooting PSTN calls, use these two properties to understand why the call ended as follows:
+This code is based on Session Initiation Protocol (SIP) response codes. For more information, see Wikipedia's [list of SIP response codes](https://en.wikipedia.org/wiki/List_of_SIP_response_codes).
 
-- **`ParticipantEndReason`**: A three-digit code that shows the general call status. This code explains why the call ended, and groups failures by category. For example, `ParticipantEndReason 404` tells us that caller/callee wasn't found, `ParticipantEndReason 500` means that a service error occurred, and so on. This code is based on the SIP response codes. For more information, see Wikipedia's [List of SIP response codes](https://en.wikipedia.org/wiki/List_of_SIP_response_codes).
+### ParticipantEndSubCode
 
-- **`ParticipantEndSubCode`** : A more specific response code, usually six digits long, that explains in greater detail why there was a problem with the call.
+`ParticipantEndSubCode` is a more specific response code that's usually six digits long. It explains in greater detail why there was a problem with the call.
 
-## Understanding the ParticipantEndSubCode relationship
+A key factor in troubleshooting Azure Communication Services PSTN calls is determining whether the final SIP response code for the call came from a Microsoft process or the user's/operator's session border controller (SBC). An easy way to determine where the code originated is to look at the `ParticipantEndSubCode` response.
 
-A key factor in troubleshooting Azure Communication Services PSTN calls is determining whether the final response code for the call comes from a Microsoft process or the users/operators Session Border Controller (SBC). An easy way to determine where the code originated is to look at the `ParticipantEndSubCode` response.
+If the `ParticipantEndSubCode` value starts with `560`, it indicates that the user's/operator's SBC generated the response code. In that case, you should check your SBC configuration.
 
-If the `ParticipantEndSubCode` starts with **560**, it indicates that the response code is generated by the users/operators Session Border Controller (SBC), so developers should check their SBC configuration.
+For example, if the `ParticipantEndSubCode` value is `560403`, it means that the SBC generated the final response code, and the code is `403`. In that case, you should start troubleshooting the calls by using the SBC logs.
 
-- For example, if the `ParticipantEndSubCode` is **560403**, it means that the final response code is generated by the SBC, and the last three digits indicate SIP response code **403**. In this case, a developer should start troubleshooting the calls using the SBC logs.
+For `ParticipantEndSubCode` responses that don't start with `560`, the Microsoft service generated the final response code.
 
-For all other `ParticipantEndSubCode` responses that don't start with **560**, the final response code is generated by a Microsoft service.
+## Related content
 
-## Detailed information on individual error codes
-
-For more information about common error codes and suggested actions, see [Troubleshooting call end response codes for Calling SDK, Call Automation SDK, and PSTN calls](../../resources/troubleshooting/voice-video-calling/troubleshooting-codes.md).
-
-## Related articles
-
-For more information, see [Troubleshooting in Azure Communication Services](../troubleshooting-info.md).
+- For general troubleshooting information, see [Troubleshooting in Azure Communication Services](../troubleshooting-info.md).
+- For detailed information about common error codes and suggested actions, see [Troubleshooting call end response codes for Calling SDK, Call Automation SDK, and PSTN calls](../../resources/troubleshooting/voice-video-calling/troubleshooting-codes.md).