Overview

555 RTC SDK provides APIs which allow iOS developers to create apps with different features like Audio/Video/PSTN call, conference call, chat, screen sharing, etc. The services offered by SDK are supported by 555 platform's reliable and scalable infrastructure designed to handle a large number of calls.

Below steps allow the user to make an end-to-end PSTN call. This includes user authentication, login, notification creating media connection.

1. Follow installation guide to integrate SDK into your project.
2. From 555 portal, get an API key and access token.
3. Complete login to get the JWT which is needed to access any SDK or backend APIs.
4. Follow notification guide to add support for APNS notification in your app.
5. Use below SDK API document to make incoming/outgoing PSTN calls.

Usage

PSTN Call

This document list down all the SDK API calls and their usage for making incoming/outgoing PSTN calls and using advance call features like call hold/unhold, mute/unmute, etc.

Before initiating or accepting a PSTN call, make sure you have logged in to 555 platform.

SDK initialization

Below API initializes and sets the context for the SDK. It is advisable to call this API at the launch of the application.

Rtc555Sdk.initializeLibrary()

Adding SDK configuration.

To make PSTN/Voice related API call, SDK should have below mentioned mandatory configuration data to establish a connection with the 555 platform backend.

let config:Rtc555Config = Rtc555Sdk.sharedInstance.getConfig()
config.phoneNumber =  // Source Telephone Number
config.routingId =  // 555 platform login response will provide unique id for the logged in user.
config.url =  // Event manager URL
config.token =  /// 555 platform login response will provide unique jwt token for the logged in user.

Rtc555Sdk.setConfig(config: config)

Initiating an Outgoing Call

To make outgoing calls, pass destination telephone number, notification payload to dial API. Notification payload contains two fields called data and notification. Users can add any custom data as part data key which will get delivered to the remote end as part of the notification. The notification key contains the notification type and federation type of the notification (Both values are already populated in the below example).

dial API returns enum Result. A successful dial API call with return call Id, failure case return error code and the reason for the error.

Rtc555Voice.dial( number: targetTelephoneNumber, notificationPayload:buildNotificationPayload()){ result in
           switch result {
           case .success(let callId):
               print("Dial was success and callid is = \(callId)")
           case .failure(let error):
            print(error)
           }
       }
       
 //build notification  payload
 private func buildNotificationPayload() -> String{
     let data = ["cname" : <Source Telephone Number>,    // source telephone number
                 "cid" : <Source Telephone Number>,      // source telephone number
                 "tar" : <Target Telephone Number>]    // target telephone number

    let notificationPayload = ["type" : "pstn",
                               "topic": "federation/pstn"]


    let userData = ["data": data, "notification" : notificationPayload]

    do{
        let jsonData = try JSONSerialization.data(withJSONObject: userData, options: JSONSerialization.WritingOptions.prettyPrinted)

        return String(data: jsonData, encoding: String.Encoding.utf8)!
    }catch {
        Log.e("Error creating notification payload")
    }
    return " "
}
       

Below is the Notification payload need to be build for outgoing notificationData:

Note: Please make sure to add mandatory microphone permission in your info.plist file before accessing Dial/Accept call APIs to allow SDK to create local audio stream

Accept/Reject an Incoming Call

When user receives an incoming PSTN call alert, the user can choose to:

• Accept call
• Reject call

Accept Call

If the user wants to accept the incoming PSTN call request, use accept API and pass the notification payload received from incoming APNS push notification. accept API returns enum result. Success case of result will return call id and failure case return error code and reason for the error.

Rtc555Voice.rtcDelegate = self
Rtc555Voice.accept(notificationData: notificationdata){ result in
            switch result {
            case .success(let callId):
                print("callId :: \(callId)")
                 self.callId = callId
            case .failure(let error):
             print(error)
            }
        }

Pass notification payload received at incoming notification.

Reject Call

Users can reject an incoming call using reject API. Pass notification payload received in incoming APNs push notification.

Rtc555Voice.reject(notificationData: notificationdata){ result in
            switch result {
            case .success(let callId):
                print("Reject was success  = \(callId)")
                 self.callId = result
            case .failure(let error):
             print(error)
            }
        }

End an Active Call

Users need to hangup API to end the active call.

Rtc555Voice.hangup(callId: callId)

Clean up the session.

Invoke below API in Rtc555Sdk to release all the resources used by SDK. This call also allows the client to disconnect with the 555 platform backend. The app developer should call this API if the app goes to the background or kill state.

Rtc555Sdk.cleanup()

On-call Features

Features offered by iOS SDK for PSTN call are:

• Hold Call
• Unhold Call
• Mute Local Audio
• Unmute Local Audio
• Merge Two Calls
• Send DTMF Tone

Hold Call

This API call allows users to hold the ongoing call. Both caller and callee won't able to hear to each other after invoking this call.

Rtc555Voice.hold(callId: callIds)

Unhold Call

This API call allows users to un-hold the already held call. Both caller and callee will hear each other after invoking this call.

Rtc555Voice.unhold(callId: callId)

Mute Local Audio

This API call allows users to mute it's audio in the call.

Rtc555Voice.mute(callId: callId)

Unmute Local Audio

This API callow user to un-mute it's audio in the call.

Rtc555Voice.unmute(callId: callId)

Audio Call Delegates

To get call status or error report during the call, implement Rtc555SdkDelegate protocol and initialize the voice delegate as below

Rtc555Voice.rtcDelegate = self

onStatus

This callback gets invoked when we receive the status of an ongoing PSTN call.

    func onStatus(status callStatus: CallStatus,id callId:String) {
         
     }

Status:

• initializing   -   When the call is initializing
• connecting   -   When the call is connecting
• connected    -   When the call is connected
• disconnected  -   When the call is disconnected
• hold       -   When the call is hold

onError

This callback gets invoked when we receive an error from an ongoing PSTN call.

    func onError(error errorInfo: Error,id callId:String) {
         
     }

onNotification

In case you want to use XMPP notification (Instead of APNS), using this optional delegate call. The client needs to be connected to 555 backend to avail of this notification callback.

    @objc func onNotification(notification notificationData: [AnyHashable : Any]) {

    }