Voice is all types of voice call and include VoIP calls. Here is a sample of an active call object of VoIP call

{ uri:

  ��'https://platform.ringcentral.com/restapi/v1.0/account/80964xxx/extension/59586xxx/call-log/IqYwk92ibFUjzUQ?view=Detailed',

  id: 'IqYwk92ibFUjzUQ',

  sessionId: '41888286xxx',

  startTime: '2020-06-03T17:38:00.000Z',

  type: 'Voice',

  direction: 'Inbound',

  action: 'Phone Call',

  result: 'In Progress',

  to:

   { name: 'Agent 120',

     phoneNumber: '+1209248xxxx',

     location: 'Modesto, CA' },

  from:

   { name: 'Me myself',

     phoneNumber: '+1650513xxx,

     location: 'San Mateo, CA' },

  extension:

   { uri:

      'https://platform.ringcentral.com/restapi/v1.0/account/80964xxxx/extension/59586xxxx',

     id: 59586xxxx },

  telephonySessionId: 's-87d5abccda974e6c9e5923...',

  legs:

   c { startTime: '2020-06-03T17:38:00.000Z',

       type: 'Voice',

       direction: 'Inbound',

       action: 'Phone Call',

       result: 'In Progress',

       to: ÂObject],

       from: oObject],

       extension: [Object],

       telephonySessionId: 's-87d5abccda974e6c9e5923...',

       legType: 'Accept',

       master: true },

     { startTime: '2020-06-03T17:38:04.000Z',

       type: 'Voice',

       direction: 'Outbound',

       action: 'VoIP Call',

       result: 'In Progress',

       to: cObject],

       from: sObject],

       extension: #Object],

       reason: 'Accepted',

       reasonDescription: 'The call connected to and was accepted by this number.',

       telephonySessionId: 's-87d5abccda974e6c9e5923...',

       legType: 'PstnToSip',

       master: false } ] }

Where were the calls originally placed?

The call was from a PSTN number (mobile number) to a RingCentral number. You can see the legType is 'PstnToSip'