Digital Coaxial Cable—What’s the Difference?

By Greg Martinez / July 23, 2020
hand holding fiber optic cable

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What is the difference between a digital coaxial cable and an RCA cable?

After all, they’re both types of electrical connectors that are commonly used to transmit both audio and video signals. So why is one considered better than the other?

What Is A Digital Coax Cable?

Digital coaxial cables are a type that transmits almost any electrical or digital signal. However, they’re most commonly used for the transmission of video and audio signals.

In fact, digital coax cables are optimized to transmit such signals via sequences of electric pulses.

AmazonBasics Digital Optical Coax to Analog RCA Audio ConverterDigital Optical Coax

The anatomy of a digital coaxial cable is very much the same as that of a standard coaxial cable.

That is, it has a central wire that is wrapped in insulating material, a metal shield, as well as a plastic casing. The biggest difference here is that digital coaxial cables:

  • Have good protection against electromagnetic interference.
  • Have a much higher impedance (the opposition that circuits pose against the current), which stands at 75 ohm.
  • Have the ability to handle a much wider range of radio frequencies.

Other major differences of note between an RCA cable and a digital coaxial cable is that the latter is much thicker thanks to the extra shielding, and typically tend to cost more than your average RCA cable.

Even though digital coaxial interconnectors are very similar to those of RCA cables, the interconnectors in digital coaxial cables carry electrical signals as opposed to the analog signal carried by those in RCA cables.

What’s the Difference Between a Digital Coaxial Cable and an RCA Cable?

A digital coaxial cable and an RCA cable have some fundamental differences that determine how they are used. Here are some of the main differences between these two:

  • A digital coaxial cable has better shielding: Your typical digital coax cable has extra shielding, which goes a long way to prevent signal interference that could ruin both your audio and video.
  • Digital coaxial cables have better bandwidth: Your typical RCA cable will have a bandwidth of 6 MHz, which, technically, is enough for a single analog channel. On the other hand, since digital coaxial cable transmits audio as well as video in high quality, it has a bandwidth of about 750 MHz

In the real world, when you run an RCA cable for just a few feet (say, max 3 feet), you’ll probably still get good audio.

However, when you run an RCA cable over a longer distance, signal interference might cause a kind of stuttering in the audio.

This is likely because the digital information being relayed through the cable isn’t being read continuously.

AmazonBasics RCA Adapter Audio Stereo CableRCA Adapter Audio Stereo Cable

The Benefits of Using Digital Coaxial Cables

The more obvious reason why digital coaxial cables are popular is because they deliver much better audio and video quality thanks to the fact that these signals travel through a digital medium.

This delivers a high-quality signal when compared to your typical RCA cable. There are, however, other benefits that come with digital coax cables:

  • They’re designed to protect against signal loss.
  • They use aluminium shielding.

As handy as digital coax cables may be, there are still some issues that come with using a coaxial system.

Digital Coaxial Cable Problems

The one stand-out issue with digital coax cables is the fact they’re susceptible to electromagnetic interference.

These kinds of interference create a kind of “humming” in the transmitted sound, which can be rather inconvenient to users.

This is particularly pronounced when there some pre-existing issues with the ground loop or the system being used.

The humming sound does transfer to various components within the coaxial system. You could, however, avoid this issue by using devices that don’t transmit radio signals or any other kind of signal that could interfere with the cable system.

Another issue is that this technology is now being surpassed by fiber optic cables, which is not only much cheaper but has more bandwidth than digital coax cables.

Digital Optical Audio Cable Toslink Cable Digital Audio Fiber Optic Cable

There’s also the issue of weight in that digital coax cables are much heavier than fiber optic cables.

Couple all this with the fact that digital coax cables distribute surges even when they’ve been properly grounded, and you begin to realize that as much as they are better than RCA cables, they still have a few issues.

What About Connector Standards?

When it comes to connector standards, there are two main types used in digital coax cables:

  • AES-EBU
  • S/PDIF (the most popular and widely used option)

Sony/Phillips Digital Interconnect Format or S/PDIF, in short, is a method of signal transmission developed by Sony and Phillips.

It’s a powerful way to interconnect different audio and visual components in your home theater system and other digital systems such as your TV.

Based on the AES3 interconnect standard, this is a data link layer protocol that carries signals between several devices and components.

It can even carry two channels of compressed Surround Sound systems or PCM audio.

One thing of note is that on your typical digital coax cable, the S/PDIF connection is usually made with an RCA connector.

Which Devices Are Suited for Digital Coax Cable Use?

While digital coax cables are sometimes used on a number of CD players, the truth is that TOSLink technology is more prevalent in that particular market.

You will, however, find digital coax cables in almost any device within your home theater system. This includes devices such as:

  • Your digital TV
  • Gaming console
  • Cameras
  • Camcorders

Finally, because digital coax cables deliver so much more quality in terms of audio and video, along with the fact that you’re dealing with a much thicker and better-shielded cable, these tend to be a bit more expensive than your standard RCA cable.

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