A research shows that VoIP at present brings in around $6 billion in revenue. Nowadays, employees use their computers to dial voice calls. Organizations are replacing their on-site hardware with web-based services by subscription that can provide integrated text and voice communications. Read more about how IP telephony is bringing back the business phone call at: : http://it.toolbox.com/blogs/voip-news/small-cells-on-the-moon-70834

The dependence of organizations on software have increased over the decade, so reducing bandwidth and maximizing data through software integration for optimal process has also become necessary. Thus CRM and telephony are the most widely used tools today. The phone/CRM scenarios are: 

No integration:  if one enters the name and phone number of the person in the CRM software and then call the person by phone then the conversation gets automatically recorded and can be used for future review purpose.

Partial integration: if the phone system is partially integrated with the CRM then one call within the CRM platform and the phone calls get automatically logged.

Full integration: it is applicable for both incoming and outgoing calls. When a call comes the number is searched in the CRM database and then for a new number a CRM lead is offered. And for old number the call gets diverted to the responsible staff who identifies the call records and details.

Options available for phone and CRM integrations are: 

Trough CRM software with integrated telephony such as Bitrix24 which is free and TalkDesk does not require any set up.

Otherwise the existing CRM can be used if it is of Salesforce or Microsoft Dynamics and readymade integration with IP telephony providers such as RingCentral or RingDNA can be used. Read more at:  http://www.business2community.com/customer-experience/telephony-crm-match-made-heaven-0946844#!bwfcpF