Basic Voice Over IP VOIP

Voice over IP (VoIP) is a powerful communication tool.

Compared with the public switched telephone network (PSTN), VoIP companies offer the benefit of reducing communication and infrastructure cost.

Additionally, VoIP makes available elegant business PBX type  tools such as switching and routing that replace expensive PBX, such as simple and instant PBX failover, as well as virtual attendant, shopping, and departmental message boxes by integrating with various applications available with many established VOIP companies.

On the minus side, the quality of voice over IP is currently less reliable than PSTN.
Since the Internet essentially works as a best effort service, and voice data once processed and sent cannot be retransmitted, voice intelligibility may suffer from packet loss, delay, and jitter due to interference from other data packets.

For voice communication this may be of little concern, however, in applications where signal quality is critical, such as audio conferencing or recorded interviews for radio broadcast, the echo caused by delay can be disastrous.

In wireless networks, such problems may be made worse by various characteristics of wireless media, including reduction of signal strength and radio interference. Additionally, there are security issues related to VoIP communications.

See how it's done right:

RingCentral, Inc. is a leading provider of flexible and cost-effective software as a service (SaaS) solutions for business communications, including a cloud-based contact center solution and Glip, an advanced team collaboration workspace.
Our flagship cloud PBX phone system utilizes VoIP (voice over internet protocol) technology to eliminate the need for on-premise PBX hardware. This allows our customers to communicate via voice, text, and fax on multiple devices—including smartphones,
tablets, computers, and desk phones—using company 800 numbers that enable toll-free inbound calls.

Resources:

Managing the PSTN Transformation
A Blueprint for a Successful Migration to IP-Based Networks

PING Basic IP Network Troubleshooting - Jorgen Lanesskog

Introduction_to_Communications_Technologies_A_Guide_for_Non-Engineers-_Third_Edition

How a Network Works

VoIP for Business: Using Internet Telephony to Increase Service Levels and Cut Costs

Beyond VoIP Protocols: Understanding Voice Technology and Networking Techniques