Paul Neill (6 September 1882 – October 1968) and Carl Concelman (23 December 1912 – August 1975) must be turning in their graves. With ever increasing video resolution and advancing network technology, the European Broadcast Union (EBU) is currently discussing the possibility of replacing the humble BNC (Bayonet Neill Concelman Connector) with the RJ45 connector.

Paul Neill was an electrical engineer at Bell Labs and Carl Concelman an engineer at Amphenol, which was founded in Chicago in 1932 by entrepreneur Arthur Schmitt. Its first product was a tube socket for radio tubes.

Amphenol expanded significantly during World War II, when the company became the primary manufacturer of connectors used in military hardware, including airplanes and radios. It was while at Amphenol that Concelman was credited for inventing the C connector, a robust connector used for terminating coaxial cable that carried radio frequencies in a multi-megahertz range.

While at Bell Labs, Neill worked in the Electrical Research Products division in the 1940s. The rapid advance in the quality of film sound during that period is credited as being largely due to two main lines of work with which he was closely associated, alongside motion picture engineers who were developing acoustic techniques for film.

During this post war period, Neill and Concelman got together to collaborate on the design of a bayonet type fitting for radio frequency (RF) applications that would lock two connector ends together for greater electrical efficiency, giving birth to the Bayonet Neill Concelman Connector or BNC.

The BNC was originally designed for military use and is commonly and mistakenly called the British Naval Connector. Other unofficial explanations expand the abbreviation as Baby Neill-Concelman because it is a lot smaller than N and C connectors invented by Neill and Concelman respectively.

Standard interface

Since its inception, video has been running over coaxial cable. The PL-259 or UHF connector was used widely in the black and white era until the introduction of colour television when the BNC connector became the standard electrical interface for professional video.

Since then, the BNC has survived transitions from analogue to digital and the subsequent explosion of digital video formats. In its inception, the development of the Serial Digital Interface (SDI) in broadcast television had a number of key design criteria, one of which was that it be carried on a BNC connector.

The BNC connector has processed television signals from the war in Vietnam through to Space Shuttle launches and the building of the International Space Station, to South Africa winning the Cricket Test Series in England; clinching the number one spot.

So after 50 years, is it time for the television industry to start looking at a different interface for video signals? A number of years ago, the world of SDI and Internet Protocol (IP) technology started coming together in the area of video transport. The Society of Motion Picture and Television Engineers (SMPTE) implemented the SMPTE 2022 family of standards in 2007.

SMPTE 2022 led to Information Technology (IT) engineers experimenting with IP streaming of professional video streams, successfully transporting a bit-for-bit copy of an SDI signal thousands of miles away.

The shift

Today almost every piece of professional TV equipment connects to an IP network in one way or another. Broadcast engineers have had to shift into the IT world’s way of thinking as well as keep up with traditional television technology. With 4K the adopted resolution in digital cinema having become common place and 8K or Super Hi-Vision looming on the horizon, there is certainly no evidence that the advance in video bit-rates are slowing down.

At one time it was not possible to convey real-time video and audio over computer networks. Today’s IT infrastructure allows such signals to be processed even if only experimental and under test conditions. Indeed Japanese broadcaster NHK has already managed to transmit its 4 000 scan lines, 7 680 x 4 320 pixels, Ultra High Definition widescreen system over an IP network!

Admittedly it was over a massive fibre optic network, using dense wavelength division multiplexing requiring a total of 16 different wavelength signals to get the bit rate high enough.

So why move from HD SDI and Audio Engineering Society (AES) over to BNC? It’s all about the IT world keeping up with the broadcast world and boils down to cost savings and the ability for IT platforms to adapt to anything thrown at them.
Doing this, however, requires one significant, difficult and costly change: it will require a break in the connection between video format geometry and the electrical and physical interface of the famous connector.

So is it really time to say goodbye to the BNC? Methinks no, not yet!

By Ian Dormer