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Receive speech-to-text for different languages

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This example goes over how you can use the Symbl.ai Telephony API to receive a speech-to-text transcription of a conversation in many different languages. This example uses both the JavaScript SDK and native JavaScript.

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Note

We only support English language in Streaming & Telephony API at the moment.
We support languages other than English only for our enterprise plan.
Please feel free to reach out to us at [email protected] for any queries.

Currently, the PSTN connection requires a US phone number. You can use a SIP connection to connection to a SIP URI instead. Learn more about how to connect using SIP.

Connect

When we're connecting to the Web Socket, we can define which language we use in the configuration. Here we will set the languageCode key to Spanish (es-US). You can view the full list of supported languages here. After you make the connection the phone number you specified will be dialed and you can begin speaking in the language you specified.

Once the connection is finished you will receive a Conversation ID which you can use with our Conversation API to get a speech-to-text transcription. You can learn how to receive speech-to-text from the Conversation API here.

Authentication

Before continuing, you must generate an authentication token (AUTH_TOKEN) as described in Authentication.

Configuration Snippet

Here you set the language key to Japanese: "languages": ["ja-JP"], and the timezone to Tokyo: "timezone": "Asia/Tokyo".

{
  "operation": "start",
  "endpoint": {
    "type" : "pstn",
    "phoneNumber": "phoneNumber"
  },
  "languages": ["ja-JP"],
  "timezone": "Asia/Tokyo",
  "actions": [{
    "invokeOn": "stop",
    "name": "sendSummaryEmail",
    "parameters": {
      "emails": [
        "[email protected]"
      ]
    }
  }],
  "data" : {
    "session": {
      "name" : "My Meeting"
    }
  }
}

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The Symbl SDK (Node.js) snippet must be run using Node.js, while the Native Javascript snippet can be run in your web browser.

cURL Code Example

curl -k -X POST "https://api.symbl.ai/v1/endpoint:connect" \
     -H "accept: application/json" \
     -H "Content-Type: application/json" \
     -H "X-API-KEY: $AUTH_TOKEN" \
     -d $'{
      "operation": "start",
      "endpoint": {
        "type" : "pstn",
        "phoneNumber": "PHONE_NUMBER" # 
      },
      "languages": ['ja-JP'],
      "timezone": "Asia/Tokyo",
      "actions": [{
        "invokeOn": "stop",
        "name": "sendSummaryEmail",
        "parameters": {
          "emails": [
            "[email protected]"
          ]
        }
      }],
      "data" : {
        "session": {
           "name" : "My Meeting"
        }
      }
    }'

Testing

Open up your shell terminal and copy in the command. Replace the placeholder values with the proper values and hit enter.

Node.js Code Example

const {sdk, SpeakerEvent} = require("symbl-node");
const appId = appId;
const appSecret = appSecret;

sdk.init({
  appId: appId,
  appSecret: appSecret,
  basePath: "https://api.symbl.ai",
}).then(async() => {
  console.log('SDK initialized.');
  try {
    const phoneNumber = "PHONE_NUMBER";  // Telephony API currently only supports US phone numbers.

    sdk.startEndpoint({
      endpoint: {
        type: "pstn",
        phoneNumber: phoneNumber,
      },
      languages: ["ja-JP"],
      timezone: "Asia/Tokyo",
      actions: [
        {
          invokeOn: "stop",
          name: "sendSummaryEmail",
          parameters: {
            emails: [
              "[email protected]"
            ],
          },
        },
      ],
      data: {
        session: {
          name: "Meeting name",
        },
      },
    }).then((connection) => {
      const connectionId = connection.connectionId;
      console.log("Successfully connected.", connectionId);
      console.log('Conversation ID', connection.conversationId);
      console.log('Full Conection Object', JSON.stringify(connection, null, 2));
    })
    .catch((err) => {
       console.error("Error while starting the connection", err);
    });
  } catch (e) {
    console.error(e);
  }
}).catch(err => console.error('Error in SDK initialization.', err));

Testing

Create a JavaScript file named app.js and copy this code into the file. Fill in the placeholder values with the proper values. Use npm to install the required libraries: npm install symbl-node. Now in the terminal run

$ node app.js

If successful you should receive a response in the console.

Native JavaScript Code Example

const phoneNumber = PHONE_NUMBER;
const emailAddress = EMAIL_ADDRESS;
const authToken = AUTH_TOKEN;

const payload = {
  "operation": "start",
  "endpoint": {
    "type" : "pstn",
    "phoneNumber": phoneNumber
  },
  "languages": ["ja-JP"],
  "timezone": "Asia/Tokyo",
  "actions": [{
    "invokeOn": "stop",
    "name": "sendSummaryEmail",
    "parameters": {
      "emails": [
        emailAddress
      ]
    }
  }],
  "data" : {
    "session": {
      "name" : "My Meeting"
    }
  }
}

const endpoint = 'https://api.symbl.ai/v1/endpoint:connect';
const fetchData = {
  method: "POST",
  headers: {
    'X-API-KEY': `${authToken}`,
    'Content-Type': 'application/json',
  },
  body: JSON.stringify(payload),
}

fetch(endpoint, fetchData).then(response => {
  if (response.ok) {
    return response.json();
  } else {
    throw new Error('Something went wrong on api server!');
  }
}).then(response => {
  console.log('response', response);
  console.log('conversation ID', response.conversationId);
  console.log('connection ID', response.connectionId);
}).catch(error => {
  console.error(error);
});

Testing

Open up your browser's development environment and copy this code into the console. Replace the placeholder values with the proper values.

If successful you should receive a response in the console.

Python Code Example

import json
import requests

url = "https://api.symbl.ai/v1/endpoint:connect"

# set your access token here. See https://docs.symbl.ai/docs/developer-tools/authentication
access_token = 'your_access_token'

payload = {
    "operation": "start",  # enum([start, stop]) - Start or Stop connection
    "endpoint": {
        # Object containing Type of the session - either pstn or sip, phoneNumber which is the meeting number symbl should call with country code prepended and dtmf which is the conference passcode.
        "type": "pstn",
        "phoneNumber": phoneNumber,  # Phone number including country code
    },
    "languages": ["ja-JP"],
    "timezone": "Asia/Tokyo",
    "actions": [{
        # actions that should be performed while this connection is active. Currently, only one action is supported - sendSummaryEmail
        "invokeOn": "stop",
        "name": "sendSummaryEmail",
        "parameters": {
            "emails": [
                emailAddress
            ]
        }
    }],
    "languages": ['en-US'],  # The first language code in the array is used to specify the session’s language.
    "data": {  # Object containing a session object which has a field name corresponding to the name of the meeting
        "session": {
            "name": "My Meeting"
        }
    }
}

headers = {
    'X-API-KEY': access_token,
    'Content-Type': 'application/json'
}

responses = {
    400: 'Bad Request! Please refer docs for correct input fields.',
    401: 'Unauthorized. Please generate a new access token.',
    404: 'The conversation and/or it\'s metadata you asked could not be found, please check the input provided',
    429: 'Maximum number of concurrent jobs reached. Please wait for some requests to complete.',
    500: 'Something went wrong! Please contact [email protected]'
}

response = requests.request("POST", url, headers=headers, data=json.dumps(payload))

if response.status_code == 201:
    # Successful API execution
    print("conversationId => " + response.json()['conversationId'])  # ID to be used with Conversation API.
    print("connectionId => " + response.json()['connectionId'])
    # Ephemeral connection identifier of the request, to uniquely identify the telephony connection. Once the connection is stopped using “stop” operation, or is closed due to some other reason, the connectionId is no longer valid
    print("resultWebSocketUrl => " + response.json()['resultWebSocketUrl'])
    # objSame as eventUrl but over WebSocket. The latency of events is lower with a dedicated WebSocket connection.ct
    print("eventUrl => " + response.json()['eventUrl'])
    # REST API to push speaker events as the conversation is in progress, to add additional speaker context in the conversation. Example - In an on-going meeting, you can push speaker events
elif response.status_code in responses.keys():
    print(responses[response.status_code] + ", Debug Message => " + str(response.text))  # Expected error occurred
else:
    print("Unexpected error occurred. Please contact [email protected]" + ", Debug Message => " + str(response.text))

exit()

Testing

Create a Python file named app.py and copy this code into the file. Fill in the placeholder values with the proper values. Use Python PIP (learn how to install here) to install Python Requests (pip install requests). In your termninal, now run:

$ python app.py

If successful you should receive a response in the console.

Running this code should connect our API to your phone call. Once the call is completed you will receive an email that details the conversation and provides you with a transcription and Insights about the call.

Response

If successful, you will receive a response in the console as shown below:

{
    "eventUrl": "https://api.symbl.ai/v1/event/f31ad3b9-341a-4950-a1c2-152f08da8aaa",
    "resultWebSocketUrl": "wss://api.symbl.ai/events/f31ad3b9-341a-4950-a1c2-152f08da8aaa",
    "conversationId": "5687907911204864",
    "connectionId": "f31ad3b9-341a-4950-a1c2-152f08da8aaa"
}

Response Parameters

FieldDescription
eventUrlREST API to push speaker events as the conversation is in progress, to add additional speaker context in the conversation. Example - In an on-going meeting, you can push speaker events.
resultWebSocketUrlSame as eventUrl but over WebSocket. The latency of events is lower with a dedicated WebSocket connection.ct.
connectionIdEphemeral connection identifier of the request, to uniquely identify the telephony connection. Once the connection is stopped using “stop” operation, or is closed due to some other reason, the connectionId is no longer valid.
conversationIdRepresents the conversation - this is the ID that needs to be used in conversation API to access the conversation.

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If you have any questions or concerns about our API, you can join our Support Slack or send us an email at [email protected]

Updated over 1 year ago