• Jacek Jarmulak

Voicegain releases Telephony Bot APIs for telephony IVRs and bots

Updated: Aug 4, 2021

Update Dec 2020: We have renamed RTC Callback APIs to Telephony Bot APIs to better reflect what developers can do with these APIs.

If you always wanted to build you own telephony based Voice Bot or a speech-enabled IVR but did not know where to start then we have something for you - Release 1.12.0 of Voicegain Speech-to-Text Platform now includes Telephony Bot APIs (formerly called RTC Callback APIs in the past).

With this, a web backend developer can design, code, and launch a brand new telephony based voice bot or speech IVR in a day. You can code the application logic in a programming language of your choice - Java, Python, Node.js - as long as it is able to serialize data into the JSON format. Developers can also code and deploy the application logic in a serverless computing environment like Amazon Lambda.

Many enterprises - in banking, financial services , health care, telecom and retail - are stuck with legacy telephony based IVRs that are approaching obsolescence.

Voicegain's Telephony Bot APIs provide a great future-proof upgrade path for such enterprises. Since these APIs are based on web callbacks, they can interact with any backend programming language. So any backend web developer can design, build and maintain such apps.

Why should you use Telephony Bot APIs?

With Telephony Bot APIs, integration becomes much simpler for developers. You can invite the Voicegain Speech-to-Text platform to a SIP/RTP session as long as is needed. We support SIP integration with CPaaS platforms like Twilio and Signalwire and CCaaS platforms like Genesys, Cisco and Avaya. We also support direct phone number ordering and SIP Trunks from Amazon Voice Connector. More integrations will be added soon.

Telephony Bot APIs are based on web callbacks where the actual program/ implementation is on the Client side and the Voicegain Telephony Bot APIs define the Requests and Responses. The meaning of Requests and Responses is reversed w.r.t what you would see in a normal Web API:

  • Responses provide the commands, while

  • Requests provide the outcome of those commands.

Illustrated example of Telephony Bot API in action

Below is an example of a simple phone call interaction which is controlled by Telephony Bot API. The sequence diagram shows 4 callbacks during a toy survey call:

  • Req 1: Phone Call arrived

  • Resp 1: Say: "Welcome"

  • Req 2: Done saying "Welcome"

  • Resp 2: Ask: "Are you happy", bind reply to happy var

  • Req 3: Caller's answer was "yes", happy=YES

  • Resp 3: Disconnect

  • Req 4: Disconnected

  • Resp 4: We are done

Currently supported actions

Telephony Bot API supports 4 types of actions:

  • output: say something - TTS with a choice of 8 different voices is supported

  • input: ask question - both speech input and DTMF are supported. For speech input you can use GRXML, JSGF or built-in grammars

  • transfer: transfer a call to a phone destination

  • disconnect: end the call

Wait, there is more

Each call can be recorded (two channel recording) and then transcribed. The recording and the transcript can be accessed from the portal as well as via the API.


Features coming soon:

  • record Callback action - you can use it to implement voicemail or record other types of messages

  • transfer to a sip destination

  • input - allow choice of large vocabulary speech-to-text in addition to grammars - use the captured text in your NLU

  • answer call at a sip address - instead of a phone number

  • WebRTC support

  • outbound dialing

Further Reading

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