topic Re: How to deal with Incoming PSTN call in Discussion Forum

How to deal with Incoming PSTN call

Dylan — Tue, 09 Jan 2024 09:53:17 GMT

Hi,

From PSTN call To Sinch virtual number, How should it be handled on the server side and what SVAML should be returned?

The expectation is that this call will be pushed to my device, which has the iOS SDK integrated.

This is a person-to-person call, not a conference call.

Re: How to deal with Incoming PSTN call

Roland_Ian — Mon, 08 Jan 2024 15:35:03 GMT

Hi,

You cannot call directly from PSTN to an In-app you will have to use a conference.

Pre-requisite

Start an in-app SDK client (user123)

Incoming PSTN call to a Sinch Virtual number

PSTN originating call to Sinch Virtual Number -> (ICE) -> (your Backend) -> (SVAML ConnectConf) (e.g.myconfid123)

PSTN leg is now in conference myconfid123

Conference callout using calling API In parallel (or after you get the ICE above. )

conferenceCallout using destination -> endpoint -> username (user123)

In-app leg is now in conference myconfid123

https://developers.sinch.com/docs/voice/api-reference/voice/tag/Callouts/#tag/Callouts/operation/Callouts!path=conferenceCallout/destination&t=request

Poll the conference for participants

(If you want to see which parties are still in Conference)

https://developers.sinch.com/docs/voice/api-reference/voice/tag/Conferences/#tag/Conferences/operation/Calling_GetConferenceInfo

Hangup the call on the incoming DICE (from in-app let)

Hope this helps.

Re: How to deal with Incoming PSTN call

Dylan — Tue, 09 Jan 2024 02:55:31 GMT

Is a conferences necessary?

So what does connectMxp do and how is it used?

Re: How to deal with Incoming PSTN call

Dylan — Tue, 09 Jan 2024 03:07:48 GMT

I'm talking between two people. conference doesn't fit my scenario. What I expect is that after dialing a Sinch number, Sinch can push a call to the device. How can this be achieved?

Re: How to deal with Incoming PSTN call

Roland_Ian — Tue, 09 Jan 2024 07:42:02 GMT

Sorry, we do not support direct PSTN origination call to in-app Voice SDK client. You have to use a conference to anchor the media portion of the call for the in-app leg.

A word about push:

This would be either FCM or APN depending if the handset is Android or Apple. The push would be sent to the device for:
- media connection to the conference after the conference callout
- media connection to the in-app peer (or proxy to peer) depending on the external network restrictions. After another in-app Voice SDK client has placed a call to another in-app Voice SDK client

Direct calling support

You can however achieve the other way round in-app -> PSTN

Re: How to deal with Incoming PSTN call

Dylan — Tue, 09 Jan 2024 07:51:07 GMT

Thanks, I may not have phrased it clearly.

My usage scenario is to use a non-Sinch number (could be a real number or another virtual number) to call a number purchased on a sinch. The number is already pointing to an applicantion, and then the APN key is configured, and the iOS SDK is already integrated on the phone, what should I do to get the call pushed to the device?

What kind of SVAML should be returned by the server, please give me an example.

The conference doesn't look like it's quite what I'm looking for.

Regards,

Dylan.

Re: How to deal with Incoming PSTN call

Roland_Ian — Tue, 09 Jan 2024 09:16:28 GMT

Hi Dylan

As I stated we do not support incoming PSTN (real or virtual number) to a purchased Sinch Virtual number that then pushes to an iOS SDK (In-app Voice SDK client).

You have to use a conference to connect both legs here.

As you will see from the call scenarios listed in our documentation, phone to app is not listed.

For the SVAML connectMXP, this only works for application-to-application calls (in-app only) no phone to application.

https://developers.sinch.com/docs/voice/api-reference/svaml/actions/#connectmxp

Hope this helps clarify a little.

Re: How to deal with Incoming PSTN call

Dylan — Tue, 09 Jan 2024 09:23:48 GMT

Roland-Ian

Thank you,

So about the app-to-app call and whether or not the push can be accomplished.

I now want to do only app to app calls and incoming calls can be pushed to the device, how should this be implemented in my backend.

Regards.

Re: How to deal with Incoming PSTN call

Roland_Ian — Tue, 09 Jan 2024 09:35:32 GMT

App to App push for iOS is documented here:

https://developers.sinch.com/docs/in-app-calling/ios/push-notifications-callkit/

You will need to provide us with your APNS Authentication Signing Key

https://developers.sinch.com/docs/in-app-calling/ios/push-notifications-callkit/#configuring-an-apns-authentication-signing-key

We will then send the push to Apple and they will in turn send it to the handset.

If you use Android we will require your FCM sender id and Registration token

https://developers.sinch.com/docs/in-app-calling/android/push-notifications/

https://developers.sinch.com/docs/in-app-calling/android/push-notifications/#fcm-step-4-acquire-fcm-push-configuration

Re: How to deal with Incoming PSTN call

Dylan — Wed, 10 Jan 2024 04:36:26 GMT

Hi Roland-Ian,

Thank you.

I still have a few questions about this conference that I hope you can help answer.

1.Should the conference id set in connectConf SVAML and the conference id set via callout be set to the same, or should they be set differently?

2.I set the value of custom in the callout, but I don't receive it in the APN push, how can I set it to take effect?

3.I'm trying to get the information about the meeting, but it returns me an error,

curl -i -X GET \
-u xx:xx \
'https://calling.api.sinch.com/calling/v1/conferences/id/2000000033938953'

I'm getting it when the meeting is being set up, I don't know why it's okay to return an error.

Regards.

Re: How to deal with Incoming PSTN call

Roland_Ian — Wed, 10 Jan 2024 08:12:05 GMT

1. Yes the same conference id. Keep in mind the regional scope of conferences if your callout and sdk client are based in different regions.

Calling API

https://developers.sinch.com/docs/voice/api-reference/#api-quick-reference

https://developers.sinch.com/docs/in-app-calling/overview/#sinch-in-app-global--regional-hostnamesendpoints

2. Custom headers in call out are not compatible with headers to in-app clients.

3. Which error does it return?

Re: How to deal with Incoming PSTN call

Roland_Ian — Wed, 10 Jan 2024 08:20:10 GMT

1. Yes you should. Please keep in mind the regional scope of Conferences when connecting your clients.

Conference calls / scope

https://developers.sinch.com/docs/voice/api-reference/#conference-calls

Calling API

https://developers.sinch.com/docs/in-app-calling/overview/#sinch-in-app-global--regional-hostnamesendpoints

In-app clients

https://developers.sinch.com/docs/in-app-calling/overview/#sinch-in-app-global--regional-hostnamesendpoints

2. custom field is not supported currently in conferenceCallout to destination type: username

3. Which error is it? Can you give me an example

Re: How to deal with Incoming PSTN call

Dylan — Wed, 10 Jan 2024 08:50:04 GMT

Hi,

I have now created a new problem and need your help.

I returned SVAML on the server side specifying the conference

{"instructions":[{"name":"answer"}],"action":{"name":"connectConf","conferenceId":"2000000033938953"}}

and also called callout to set up the conference.

curl -i -X GET \
-u xx:xx \
'https://calling.api.sinch.com/calling/v1/conferences/id/2000000033938953'

Return

{"participants":[{"cli":"+12483158xxx","id":"e5fbc98b-4d1b-4e31-a527-4d13ed7d6636","duration":8,"muted":false,"onhold":false}]}

But when I go to get the conference information, I get only one member, and it looks like it's just the receiver's side that's joined the conference, and the dialing side isn't connected to the conference. So the manifestation is that the call doesn't have sound. I would like to ask how the dialing party is accessing the conference and how can I get both parties into the conference to talk normally.

Am I missing any processes? Let me know if you need any examples.

Regards.

Re: How to deal with Incoming PSTN call

Roland_Ian — Wed, 10 Jan 2024 09:08:16 GMT

I have looked and each conference leg is started in two different regions. This is due to GeoIP lookup between the IP you use to start the callout and the IP of the in-app Voice SDK client being considered as different regsions.

As outlined here: https://developers.sinch.com/docs/voice/api-reference/#conference-calls

Important!

Conference rooms have regional scope. If you want to connect multiple participants from different regions (Continents) on the same conference, you must “force” all members to be on the same region.

This can be done by selecting the same Sinch Voice API regional endpoints for Callout requests and/or the Sinch In-App regional endpoint/hostname to be used on your Mobile or Web Apps.

You can work around this, please try the following:

Can you change your in-app client URL to: https://ocra-apse1.api.sinch.com

And the callout use: https://calling-apse1.api.sinch.com/calling/v1

Re: How to deal with Incoming PSTN call

Dylan — Wed, 10 Jan 2024 09:24:38 GMT

Hi Roland_Ian,

This doesn't seem to be working. I have changed the callout url as you said

https://calling-apse1.api.sinch.com/calling/v1/callouts,

and the client url as wellhttps://ocra-apse1.api.sinch.com, and I still get the same results as before.

"callid":"50e30922-dfa5-4e53-9be2-b94c6903de14"

The SVAML returned by the server is

{"instructions":[{"name":"answer"}],"action":{"name":"connectConf","conferenceId":"2000000033938953"}}

By looking up the attendee is still a member. Please help find the information about this call to see if something is set up incorrectly, looking forward to your input.

Re: How to deal with Incoming PSTN call

Roland_Ian — Wed, 10 Jan 2024 11:16:08 GMT

Hi, I want to examine your conferences across regions I need to isolate your conference name, can you use another one than 2000000033938953 for a single test?

Thanks

Re: How to deal with Incoming PSTN call

Roland_Ian — Wed, 10 Jan 2024 14:03:12 GMT

After checking the logs.

I have looked at the logs and the URL in the ICE for the conferenceCallout portion of the call

https://calling-use1.api.sinch.com/calling/v1/calls the region contained in calling-<region> should also be used in the in-app client.

So https://ocra-use1.api.sinch.com should be used here.

It is the incoming PSTN leg that defines which reason to use.

This is due to the regional scope of conferences and the originating PSTN leg creates the conference so it will be anchored there.

Re: How to deal with Incoming PSTN call

Dylan — Thu, 11 Jan 2024 02:11:22 GMT

HI Roland_Ian,

But the PSTN is an external caller, in that the client has specified the address at the time of registration and he doesn't know what region the caller belongs to. Does it have to be consistent on the client side to work, and can you use a global address?

Re: How to deal with Incoming PSTN call

Roland_Ian — Thu, 11 Jan 2024 17:14:42 GMT

Hi Dylan,

Yes this is a limitation of conferencing being regional.

You will have to have your Sinch Client started in the region the PSTN origination leg is in for it connect to the conference in that region.

There could be creative ways around such as sending an out of band push that could then start the client before doing the conference callout, however it would be outside of the scope of the Voice SDK.

Re: How to deal with Incoming PSTN call

Dylan — Fri, 12 Jan 2024 01:44:51 GMT

Hi Roland_Ian,

Thank you.

I have no problem with this part. Now I have initiated a recording question, but no one has answered it. Please take a look at the reason.

Start recording failed - Sinch Community - 13823

As an added note, I would like to start recording anytime during a call instead of specifying recording when dialing. Now going to turn on recording during a call doesn't work, so please help me see what's going on.

Regards.