Welcome to the RingCentral Community

Here is the problem. You don't have a phone for your 101 user extension. Login your sandbox account, select the user -> numbers & phones and add a phone (select the RingCentral softphone) for your extension.

@Phong Vu Just curious to know if RC phone support any device id? As per the question, it seems device response is empty because of using RC phone.

If I check following ref:

https://community.ringcentral.com/questions/10052/callout-using-mobiledesktop-app.html

you clearly mentioned:

"The RC mobile apps and the RC Desktop app do not register a device id so that you cannot find it from the extension device list. "

Correct me if I am missing anything

If there is no way to get a deviceId for any device in the sandbox, is there ANY way to test a CallOut from the sandbox? I have a Ring Central Poly phone. Is there a way to log that into the sandbox?

Any other ideas???

Her is all what you need to implement in Node JS. Let me know if you have problem or you want in other programming language.

const RingCentral = require('@ringcentral/sdk').SDK

RINGCENTRAL_CLIENTID = 'your-app-client-id'
RINGCENTRAL_CLIENTSECRET = 'your-app-client-secret'
RINGCENTRAL_SERVER = 'https://platform.devtest.ringcentral.com'

RINGCENTRAL_USERNAME = 'username'
RINGCENTRAL_PASSWORD = 'password'
RINGCENTRAL_EXTENSION = 'ext-number'

const rcsdk = new RingCentral({
  server: RINGCENTRAL_SERVER,
  clientId: RINGCENTRAL_CLIENTID,
  clientSecret: RINGCENTRAL_CLIENTSECRET
})

var platform = rcsdk.platform();

rcsdk.login({
        username: RINGCENTRAL_USERNAME,
        extension: RINGCENTRAL_EXTENSION,
        password: RINGCENTRAL_PASSWORD
      })

platform.on(platform.events.loginSuccess, async function(e){
    console.log("Login success")
    get_extension_devices()
});

async function get_extension_devices() {
  console.log("get_extension_devices")
  try{
    var resp = await platform.get('/restapi/v1.0/account/~/extension/~/device')
    var jsonObj = await resp.json()
    for (var record of jsonObj.records){
      if (record.status == "Online"){
        console.log(record.status)
        console.log(record.id)
        call_out(record.id)
        break
      }
    }
  }catch(e){
    console.log(e.message)
  }
}

async function call_out(deviceId) {
  var params = {
    from: {
      deviceId: deviceId
    },
    to: {
      phoneNumber: "phone number to call"
    }
  }
  try{
    var resp = await platform.post('/restapi/v1.0/account/~/telephony/call-out', params)
    var jsonObj = await resp.json()
    console.log(JSON.stringify(jsonObj))
  }catch(e){
    console.log(e.message)
  }
}