S/PDIF

S/PDIF, or Sony/Philips Digital Interconnect Format, refers to the data link layer protocol and physical layer for sending audio signals between stereos and speakers. This article will go over exactly what data link layer protocols and physical layers are, what S/PDIF is and how it differs from AES3, and the differences between coaxial cables and optical cables.

What Is S/PDIF

S/PDIF was named after Sony and Philips which are the two main companies who designed the S/PDIF connection. S/PDIF stands for Sony/Philips Digital Interface Format but is often shortened to the Sony Philips Digital Interface. S/PDIF is used to transfer audio signals from your stereo equipment to your speakers. S/PDIF is based on a set of international standards of cables known as the IEC (International Electrotechnical Commission) to make sure everyone in the world can use the same audio connections no matter where they go. S/PDIF isn’t really all that different from the older AES3 model but we’ll cover that a bit later. S/PDIF can be used for a number of audio connections. S/PDIF can be used to connect DVD players to home theater projectors or televisions if the receiver supports DTS surround sound or Dolby Digital surround sound. S/PDIF can also be used to transfer signal between CD players and headphones. S/PDIF is also used in computers to transfer audio signals to multiple speakers at once.

S/PDIF vs. AES3

There are several small differences between S/PDIF and AES/EBU but the two standards are largely similar. AES3, also known as AES/EBU, was jointly invented by the Audio Engineering Society and the European Broadcasting Union in 1985. AES3 has been updated alone in both 1992 and again in 2003. Keep in mind that both S/PDIF and AES3 are standards set forth to accomodate a wide array of different connections and cables. The main difference of the AES3 and S/PDIF is that AES3 is more commonly used for professional sound recording and S/PDIF is used for more household applications. S/PDIF was created at the same time as AES3 and was made to be similar in design so that it would be easier to manufacture the cables and jacks and also so that the two cables could be interchangeable if need be. S/PDIF uses less expensive hardware than the more professional AES3 model does, which makes it practical for home use.

Coaxial Cables vs Optical Cables

S/PDIF comes in two different types of cables: Coaxial and optical. Below is a description of each so that you can see the differences in each. We will then compare the two types of cables to see which is better for your needs.

Coaxial Cables

Coaxial cables are the more traditional type of cable and have been around for decades. Coaxial cables involve a conducting metal wrapped in insulation. The insulation has a “shield” around it, which is made of a conducting material (usually aluminum foil) that’s either in a foil form or a wire braid that is woven together to make a thread. The shield is then covered with another thick layer of insulation. When a coaxial cable is in use, electricity passes through the conducting metal where the signal is generated in the the receiving device. Coaxile cables are stable and reliable, but can only be used in distances less than 100 meters. Coaxial cables are the type of cables that you use in any electronic device whether it is for audio, video, charging, or transfering information. Coaxial cables come in many different forms and are widely used around the world.

Optical Cables

Optical cables, or optical fiber cables, are cables made of plastic or glass, rather than metal, to transfer light from a transmitter to a receiver. Optical cables are also the same thing as fiber optics. Optical cables are considered better than coaxial cables because light is transmitted much faster than electricity which results in extremely high data transfer speeds. Because optical cables are very effective at keep light inside them, data loss is kept to a minimum which allows for optical cables to be used over large distances. Optical cables can also be bundled and tightly packed which is why they are quickly gaining popularity in small electronics. In fact, electronics today could not possibly be as small as they are if we did not have optical cables. The problem with optical cables, however, is that the cables must be kept straight in order for the light to reach its destination. That means that the slightest bent in the cables could prevent the information from being sent, rendering the cables useless. Optical cables must also be carefully cleaved at the ends and spliced together using an electric arc. Optical cables do have the bonus of being immune to electromagnetic interference such as incoming signals from other devices and EMP (electromagnetic pulse) weapons. Optical cables are primarily used for sensors and fiber lasers.

Compare

Now that you have an understanding of both coaxial cables and optical cables, we will compare the two. Coaxial cables can be used for short distances (under 100 meters) while optical cables can be used for long distances (thousands of meters). Coaxial cables are reliable because they can be twisted if need be while optical cables become useless if bent. Coaxial cables are vulnerable to electromagnetic interference while optical cables are not. Optical cables transfer information much faster than coaxial cables. Optical cables are more complicated than coaxial cables and cost more. Analyze all of the information that this article has provided you and decide which type of cable is better for you.