This guide covers the SIPREC Media Gateway solution pattern, which consists of the following components to receive speech audio and call signals, and return call transcripts:

• Session border controllers and media gateways for receiving call audio from your session border controllers (SBCs)
• HTTPS API to receive requests to start and stop call transcription
• Webhook to POST real-time transcripts to a designated URL of your choosing, alongside two additional APIs to retrieve transcripts after-call for one or a batch of conversations

ASAPP works with you to understand your current telephony infrastructure and ecosystem, including the type of voice work assignment platform(s) and other capabilities available, such as SIPREC.

Your ASAPP account team will also determine the main use case(s) for the transcript data to determine where and how call transcripts should be sent.

ASAPP then completes the architecture definition, including integration points into the existing infrastructure.

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Integration Steps

There are three steps to integrate AutoTranscribe into SIPREC:

1. Send Audio to Media Gateway
2. Send Start and Stop Requests
3. Receiving Transcript Outputs

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Requirements

Audio Stream Codec

With SIPREC, the customer SBC and the ASAPP media gateway negotiate the media attributes via the SDP offer/answer exchange during the establishment of the session. The codecs in use today are as follows:

• G.711
• G.729

Developer Portal

ASAPP provides an AI Services Developer Portal. Within the portal, developers can do the following:

• Access relevant API documentation (e.g. OpenAPI reference schemas)
• Access API keys for authorization
• Manage user accounts and apps

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Integrate to the Media Gateway

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1. Send Audio to Media Gateway

Media Gateway (MG) and Media Gateway Proxy (MG Proxy) components are responsible for receiving real-time audio via SIPREC protocol (acting as Session Recording Servers) along with metadata and sending to AutoTranscribe.

ASAPP offers a software-as-a-service approach to hosting MGs and MG Proxies at ASAPP’s VPC in the PCI-scoped zone.

Network Connectivity

ASAPP will determine the network connectivity between your infrastructure and the ASAPP AWS Virtual Private Cloud (VPC) based on the architecture; however, there will be secure connections deployed between your data centers and the ASAPP VPC.

• Edge layer: ASAPP has built an edge layer utilizing public IPv4 addresses registered to ASAPP. These IP addresses are NOT routed over the Internet, but they guarantee uniqueness across all IP networks. The edge layer houses firewalls and session border controllers that properly take care of full NAT for both SIP and non-SIP traffic.
• Customer connection aggregation: Connectivity to customers is done via AWS Transit Gateway, which allows establishment of multiple route-based VPN connections to customers. Sample configuration for various customer devices is available on request.

Port Details

Ports and protocols in use for the AutoTranscribe implementations are shown below. These definitions provide visibility to your security teams for the provisioning of firewalls and ACLs.

• SIP/SIPREC: TCP 5070 and above; your ASAPP account team will specify a value for your implementation
• Audio Streams: UDP <RTP/RTCP port range>; your ASAPP account team will specify a value for your implementation
• API Endpoints: TCP 443

In customer firewalls, you must disable the SIP Application Layer Gateway (ALG) and any ‘Threat Detection’ features, as they typically interfere with the SIP dialogs and the re-INVITE process.

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Generating Call Identifiers

AutoTranscribe uses your call identifier to ensure a given call can be referenced in subsequent start and stop requests and associated with transcripts.

To ensure ASAPP receives your call identifiers properly, configure the SBC to create a universal call identifier (UCID or equivalent identifier).

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2. Send Start and Stop Requests

As outlined above in requirements, user accounts must be created in the developer portal in order to enroll apps and receive API keys to interact with ASAPP endpoints.

The /start-streaming and /stop-streaming endpoints of the Start/Stop API are used to control when transcription occurs for every call media stream (identified by the GUID/UCID) sent to ASAPP’s media gateway.

See the Endpoints section to learn how to interact with them.

ASAPP will not begin transcribing call audio until requested to, thus preventing transcription of audio at the very beginning of the SIPREC session such as standard IVR menus and hold music.

Stop requests are used to pause or end transcription for any needed reason. For example, a stop request could be used mid-call when the agent places the call on hold or at the end of the call to prevent transcribing post-call interactions such as satisfaction surveys.

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3. Receiving Transcript Outputs

AutoTranscribe outputs transcripts using three separate mechanisms, each corresponding to a different temporal use case:

• Real-time: Webhook posts complete utterances to your target endpoint as they are transcribed during the live conversation
• After-call: GET endpoint responds to your requests for a designated call with the full set of utterances from that completed conversation
• Batch: File Exporter service responds to your request for a designated time interval with a link to a data feed file that includes all utterances from that interval’s conversations

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Real-Time via Webhook

ASAPP sends transcript outputs in real-time via HTTPS POST requests to a target URL of your choosing.

Authentication

Once the target is selected, work with your ASAPP account team to implement one of the following supported authentication mechanisms:

• Custom CAs: Custom CA certificates for regular TLS (1.2 or above).
• mTLS: Mutual TLS using custom certificates provided by the customer.
• Secrets: A secret token. The secret name is configurable as is whether it appears in the HTTP header or as a URL parameter.
• OAuth2 (client_credentials): Client credentials to fetch tokens from an authentication server.

Expected Load

Target servers should be able to support receiving transcript POST messages for each utterance of every live conversation on which AutoTranscribe is active.

For reference, an average live call sends approximately 10 messages per minute. At that rate, 50 concurrent live calls represents approximately 8 messages per second.

Please ensure the selected target server is load tested to support anticipated peaks in concurrent call volume.

Transcript Timing and Format

See the API Reference to learn how to interact with this API.

The expected latency between when ASAPP receives audio for a completed utterance and provides a transcription of that same utterance is 200-600ms.

Though messages are sent in the order they are transcribed, network latency may impact the order in which they arrive or cause messages to be dropped due to timeouts. Where latency causes timeouts, the oldest pending messages will be dropped first; AutoTranscribe does not retry to deliver dropped messages.

The message body for transcript type messages is JSON encoded with these fields:

Expected transcript message format:

{
  "type": "transcript",
  "externalConversationId": "<guid>",
  "streamId": "<streamId>",
  "sender": {
    "externalId": "<id>",
    "role": "customer",  // or "agent"
  },
  "autotranscribeResponse": {
    "message": "transcript",
    "start": 0,
    "end": 1000,
    "utterance": [
       {"text": "<transcript text>"}
      ]
  }
}

Error Handling

Should your target server return an error in response to a POST request, ASAPP will record the error details for the failed message delivery and drop the message.

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After-Call via GET Request

AutoTranscribe makes a full transcript available at the following endpoint for a given completed call:

GET /conversation/v1/conversation/messages Once a conversation is complete, make a request to the endpoint using a conversation identifier and receive back every message in the conversation.

Message Limit

This endpoint will respond with up to 1,000 transcribed messages per conversation, approximately a two-hour continuous call. All messages are received in a single response without any pagination.

To retrieve all messages for calls that exceed this limit, use either a real-time mechanism or File Exporter for transcript retrieval.

See the Endpoints section to learn how to interact with this API.

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Batch via File Exporter

AutoTranscribe makes full transcripts for batches of calls available using the File Exporter service’s utterances data feed.

The File Exporter service is meant to be used as a batch mechanism for exporting data to your data warehouse, either on a scheduled basis (e.g. nightly, weekly) or for ad hoc analyses. Data that populates feeds for the File Exporter service updates once daily at 2:00AM UTC.

Visit Retrieving Data for AI Services for a guide on how to interact with the File Exporter service.

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Usage

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Endpoints

ASAPP receives start/stop requests to signal when transcription for a given call should occur. Start and stop requests can be sent multiple times during a single call (for example, stopped when an agent places the call on hold and resumed when the call is resumed).

POST /mg-autotranscribe/v1/start-streaming/

Use this endpoint to tell ASAPP to start or resume transcription for a given call.

When to Call

Transcription can be started (or resumed after a /stop-streaming request) at any point during a call.

Request Details

Requests must include a call identifier with the GUID/UCID of the SIPREC call, a namespace (e.g. siprec), and an identifier from your system(s) for each of the customer and agent participants on the call.

Agent identifiers provided here can tell ASAPP whether agents have changed, indicating a new leg of the call has begun. This agent information enables other services to target specific legs of calls rather than only the higher-level call.

Requests also include a parameter to indicate the mapping of media lines (m-lines) in the SDP of SIPREC protocol; the parameter specifies whether the top m-line is mapped to the agent or customer participant. The top m-line is typically reversed for outbound calls vs. inbound calls.

Requests may also include optional parameters for transcription including:

• Language (e.g. en-us for English or es-us for Spanish)
• Whether detailed tokens are requested
• Whether call audio recording is permitted
• Whether transcribed outputs should be redacted, unredacted, or both redacted and unredacted outputs should be returned

Response Details

When successful, this endpoint responds with a boolean indicating whether the stream has started successfully along with a customer and agent object. Each object contains a stream identifier (streamId), status code and status description.

POST /mg-autotranscribe/v1/stop-streaming/

Use this endpoint to tell ASAPP to pause or end transcription for a given call.

When to Call

Transcription can be stopped at any point during a call.

Request Details

Requests must include a call identifier with the GUID/UCID of the SIPREC call and a namespace (e.g. siprec).

Response Details

When successful, this endpoint responds with a boolean indicating whether the stream has stopped successfully along with a customer and agent object. Each object contains a stream identifier (streamId), status code and status description. Each object also contains a summary object of transcription stats related to that participant’s stream.

GET /conversation/v1/conversation/messages

Use this endpoint to retrieve all the transcript messages for a completed call.

When to Call

Once the conversation is complete. Conversation transcripts are available for seven days after they are completed.

Request Details

Requests must include a call identifier with the GUID/UCID of the SIPREC call.

Response Details

When successful, this endpoint responds with an array of objects, each of which corresponds to a single message. Each object contains the text of the message, the sender’s role and identifier, a unique message identifier, and timestamps.

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Error Handling

ASAPP uses HTTP status codes to communicate the success or failure of an API Call.

• 2XX HTTP status codes are for successful API calls.
• 4XX and 5XX HTTP status codes are for errored API calls.

ASAPP errors are returned in the following structure:

{
    "error": {
        "requestId": "67441da5-dd2b-4820-b47d-441998f066e9",
        "message": "Bad request",
        "code": "400-02"
    }
}

In the course of using the /start-streaming and /stop-streaming endpoints, the following error codes may be returned:

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Data Security

ASAPP’s security protocols protect data at each point of transmission from first user authentication, to secure communications, to our auditing and logging system, all the way to securing the environment when data is at rest in the data logging system. Access to data by ASAPP teams is tightly constrained and monitored. Strict security protocols protect both ASAPP and our customers.

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Use Case Example

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Real-Time Transcription

This real-time transcription use case example consists of an English language call between an agent and customer with redaction enabled, ending with a hold. Note that redaction is enabled by default and does not need to be requested explicitly.

1. When the call record is created, ASAPP media gateway components receive real-time audio via SIPREC protocol along with metadata, most notably the call’s Avaya-formatted UCID/GUID: 00002542391662063156
2. When the customer and agent are connected, ASAPP is sent a request to start transcription for the call:

POST /mg-autotranscribe/v1/start-streaming

Request

    {
     "namespace": "siprec",
     "guid": "00002542391662063156",
     "customerId": "TT9833237",
     "agentId": "RE223444211993",
     "autotranscribeParams": {
       "language": "en-US"
     },
     "siprecParams": {
       "mediaLineOrder": "CUSTOMER_FIRST"
     }
    } 

Response

STATUS 200: Router processed the request, details are in the response body

    {
     "isOk": true,
     "autotranscribeResponse": {
       "customer": {
         "streamId": "5ce2b755-3f38-11ed-b755-7aed4b5c38d5",
         "status": {
           "code": 1000,
           "description": "OK"
         }
       },
       "agent": {
         "streamId": "cf31116-3f38-11ed-9116-7a0a36c763f1",
         "status": {
           "code": 1000,
           "description": "OK"
         }
       }
     }
    }

3. The agent and customer begin their conversation and separate HTTPS POST transcript messages are sent for each participant from ASAPP’s webhook publisher to a target endpoint configured to receive the messages.

HTTPS POST for Customer Utterance

    {
      type: "transcript",
      externalConversationId: "00002542391662063156",
      streamId: "5ce2b755-3f38-11ed-b755-7aed4b5c38d5",
      sender: {
        externalId: "TT9833237",
        role: "customer",
      },
      autotranscribeResponse: {
        message: 'transcript',
        start: 400,
        end: 3968,
        utterance: [
           {text: "I need help upgrading my streaming package and my PIN number is ####"}
          ]
      }
    }

HTTPS POST for Agent Utterance

    {
      type: "transcript",
      externalConversationId: "00002542391662063156",
      streamId: "cf31116-3f38-11ed-9116-7a0a36c763f1",
      sender: {
        externalId: "RE223444211993",
        role: "agent",
      },
      autotranscribeResponse: {
        message: 'transcript',
        start: 4744,
        end: 8031,
        utterance: [
           {text: "Thank you sir, let me pull up your account."}
          ]
      }
    }

4. Later in the conversation, the agent puts the customer on hold. This triggers a request to the /stop-streaming endpoint to pause transcription and prevents hold music and promotional messages from being transcribed.

POST /mg-autotranscribe/v1/stop-streaming

Request

    {
     "namespace": "siprec",
     "guid": "00002542391662063156",
    }

Response

STATUS 200: Router processed the request, details are in the response body

    {
     "isOk": true,
     "autotranscribeResponse": {
       "customer": {
         "streamId": "5ce2b755-3f38-11ed-b755-7aed4b5c38d5",
         "status": {
           "code": 1000,
           "description": "OK"
         },
         "summary": {
           "totalAudioBytes": 1334720,
           "audioDurationMs": 83420,
           "streamingSeconds": 84,
           "transcripts": 2
         },
       "agent": {
         "streamId": "cf31116-3f38-11ed-9116-7a0a36c763f1",
         "status": {
           "code": 1000,
           "description": "OK"
         },
         "summary": {
           "totalAudioBytes": 1334720,
           "audioDurationMs": 83420,
           "streamingSeconds": 84,
           "transcripts": 2
         },
       }
     }
    }