Voice over IP (VoIP) is the transmission of voice and multimedia communications over the internet instead of a Public Switched Telephone Network (PSTN). Other terms for voice, fax, SMS, and voice messaging that run on this technology are Internet telephony, broadband telephony, and broadband phone service.
Calling Using VoIP
Calls made using traditional telephony and voice over IP use the same steps. These include signaling, channel setup, digitization of the analog voice signals, and encoding. However, traditional telephony uses circuit-switched networks, and VoIP, packet-switched networks. VoIP transmissions utilize both proprietary and open-standard protocols. VoIP phones, special-purpose software, mobile applications, or web pages can all receive VoIP communications.
Consumer providers of voice over IP often use existing broadband internet access, and the process to make and receive calls is similar to the process of using a PSTN. In addition, some VoIP providers permit Direct Inbound Dialing (DID) to telephone extensions. The telephones or methods needed to connect to a VoIP system include the following:
- A dedicated voice over IP phone
- An analog telephone adapter such as a residential gateway or a cable modem
- Softphone applications on networked computers
Telecommunications companies commonly use VoIP telephony over dedicated and public IP networks.
Because of the bandwidth efficiency and lower costs of voice over IP, businesses favor VoIP over traditional telephone systems. In fact, as early as 2008, 80% of international Private Branch Exchanges (PBXs) were run on VoIP. VoIP offers a range of systems for small to medium and medium to large businesses. These are typically unified communication services that include phone calls, faxes, voicemail, email, and Web conferences. With VoIP, a single network can handle both voice and data, reducing infrastructure costs. Extensions on Voice over IP systems cost less than extensions using hardware-based PBXs.
VoIP devices have user-friendly interfaces that are not as rigid as PBX systems. In addition, dual-mode phones allow switching between fixed lines and mobile phones during a call. In the US, the Social Security Administration was a government innovator in using VoIP infrastructure to handle communications over its existing data network.
Quality of Service
Some experts believe that VoIP communications are less reliable than communications over circuit-switched public networks. Voice over IP may be more prone to congestion and denial of service attacks and may exhibit latency, packet loss, and jitter. These problems do not occur with circuit-switched systems that may have insufficient capacity because they refuse new connections and carry the remainder without impairment. Providers use a number of protocols that improve the quality of service and quality of experience with VoIP.
Other Considerations for Voice over IP
- Emergency Calls: Landline phones have direct relationships to locations that are available as emergency responder databases. However, vendors may provide emergency services in some countries, but in the US, the Communications and Public Service Act of 1999 requires providers to associate an address with the caller’s phone number.
- Fax Support: Fax over IP is the term for fax transmissions. Providers use the T.38 protocol to assure reliable fax communications.
- Power Requirements: Unlike traditional residential telephones, IP communications require power from electrical mains. Therefore, many internet-based systems have battery backup in the event of a power failure.
- Security: VoIP telephone systems face the same security challenges that affect any internet-connected device. However, encryption, programs, and protocols help to prevent hacking and other security concerns.
- Caller ID: As with public switched telephone networks, VoIP supports caller ID.
- Operational Costs: Voice over IP has reduced the cost of data and voice communications due to the sharing of infrastructure. A single broadband line can transmit many telephone calls. In addition, the use of virtual PBX software eliminates the need for telephone attendants and costly hardware.
- Regulatory and Legal Issues: Governments around the world are beginning to regulate IP networks and providers. In several countries, the services are taxed, prohibited, or restricted. These are more extreme measures that resulted from state-owned communications companies losing income to the new technology.
Why Voice over IP is so Beneficial
Among the most common features of Voice over IP services, the following remain the most popular: dedicated phone systems, call recording, instant messaging, screen sharing, call logs, video meetings, call forwarding, fax, virtual numbers, conferencing, and integrations. The benefits of VoIP for business systems is that it is very simple to set up and use. Furthermore, these systems accommodate mobile use at all times. Some additional benefits that are optional include extension dialing, conferencing, and music-on-hold. Voice over IP can work with local and toll free phone numbers, virtual fax extensions, and conference extensions if necessary; it’s that versatile. Users can send and receive calls from regular analog phones, IP phones, and mobile smartphones. Additionally, if you opt to use VoIP services, you may be able to keep your existing phone equipment if you purchase an analog-to-digital device.