Video Calls

Video Calls

What is Video Call

A video call is a video conferencing mode that involves two users who can see and hear each other at the same time. During a video call, users can share files and other media content, e.g. share desktop, exchange text messages, and use collaboration tools provided by their video conferencing solution.

To make video calls, video conferencing software or a separate hardware module is required. Today video calls are used almost anywhere: in meeting rooms, instant messengers, ATMs, telemedicine solutions, access control systems, etc.

History of Video Calls

Before general availability of video conferencing technology, developers had to go through a difficult patch from enormous hardware systems and sky-high prices to free software and cloud-based services.

A videophone is the very first video call device which was invented in Germany in 1936 shortly before the Olympics. Several German cities were equipped with videophone stations, where it was possible to make video calls for a charge. In 1940, the project was closed due to the outbreak of the World War II.

Toshiba videophone

In 1964, Toshiba introduced a new device — a large box with miniature screen to broadcast user’s video.

Picturephone AT&T made the next attempt to invent a video conferencing endpoint by introducing Picturephone, a small TV with a built-in camera. User’s black-and-white video was followed by a lot of interferences, as analog telephone lines were used. It cost $17 per minute to make video calls using this device, which was unaffordable for most people. After some time, Picturephone fell into the ranks of radio engineering museums.

At that time, video conferencing equipment was bulky and overpriced and still wasn’t able to provide high-quality communication. Even when the first commercially successful video conferencing equipment began to penetrate meeting rooms at the very end of the 20th century, price per endpoint did not drop below $20,000 a piece. Additionally, it was necessary to lay dedicated ISDN channels, which was even more expensive.

Our Times

Smart Watch

Today video communication is available to everybody. You don’t need any additional devices to make a video call — almost any modern TV, smartphone or laptop have support for video calls. Due to widespread use of the Internet, video calls are several times cheaper than mobile telephony.

How Video Call Works

Audio and video streams are delivered from one user to another depending on whether it is possible to directly connect users within local network or via the Internet. If direct connection is possible, media stream goes through the shortest network path bypassing the server. In this situation, the server will perform only a technical role by helping users connect to each other from different subnets and conveying service information, e.g. user statuses. The server does not bear the network load. This method is used by most popular instant messengers.


If there is no direct connection (e.g. administrator has disabled this feature), users communicate directly through the server with the appropriate load. The server will have to transmit video streams. A large number of subscribers can cause difficulties due to limited bandwidth of network interfaces. However, this is not a problem for corporate solutions, because the number of users does not usually exceed several hundred.

Not only on-premises solutions can provide users with video calling services. However, in this case you need to know a called user’s network address and be able to use it, which requires additional network settings and brings risks for enterprise security. Therefore, this method is usually used among video conferencing endpoints in meeting rooms, where each endpoint has an address, and ports are open to receive external calls.

To make video calls, subscribers can use video conferencing systems, PC software, mobile devices or browsers with WebRTC support. Until 2017, Flash technology could be used for video calls, but today it is no longer supported by major browsers.

Video Calling Software

Video calling software can be corporate or personal. Corporate video conferencing solutions are designed for use within the enterprise network. Personal video conferencing solutions are for individual use and are designed to communicate with friends and family via the Internet.

Modern video calling applications are supported by all popular platforms: Windows, macOS, Linux, iOS and Android. Therefore, users can make video calls online from desktop computers to mobile devices and vice versa.

How to Call Legacy Video Conferencing Systems and Videophones

Depending on whether your video conferencing server or client application supports SIP and H.323 protocols, you can make calls to legacy video conferencing endpoints, SIP PBXs and mobile phones. This allows you to maintain full compatibility with existing corporate communication systems. With TrueConf Server Free, you can make video calls to SIP / H.323 endpoints. For more information, read our manual on how to integrate your system with SIP / H.323 endpoints.

Video Calls in Browser

Group video call is a video conferencing session including two or more participants. Depending on the capabilities of video conferencing system, users can run various group conferences:

  • Everyone can hear and see each other (symmetric video conference);
  • Everyone can hear and see several speakers (role-based video conference);
  • Everyone can hear and see only the speaker and do not communicate with each other (video meetings);
  • Speaker cannot see or hear anybody, while everyone can see and hear the speaker (streaming);
  • Everyone can hear and see those speakers who start talking (voice-activated switching).

How to Make Group Video Calls

Thanks to WebRTC support, users can make video calls in all major browsers without installing additional plugins and software. With WebRTC, users do not need to waste their time downloading separate client applications for video calls.

Video Intercom

Video intercom or video door phone is a device used to control external access to residential buildings in the public or private territory. It consists of two parts: external module (for guests) and internal module (for people located inside the building).

External module (or call panel) is housed in a moisture-proof case with a camera, microphone, call buttons panel and loudspeaker on it. The external module is usually fixed on the wall near the entrance door or on the entrance door in a special niche.

Internal module is a telephone unit equipped with a handset for receiving calls, built-in screen for broadcasting video from the outside, speaker and control buttons.

By the number of subscribers served, secure video call devices are divided into individual (for private houses or organizations) and multiuser (for apartment blocks).

Video intercoms have no reverse video channel and media data is transmitted not through the network, but by any other suitable method—usually like in analog television.