▷ S / pdif, what is it and what is it for?

S / PDIF is a type of connection that we put to find in many electronic devices, including desktop and laptop PCs. However, many users do not know of its existence, or do not know what exactly this interface consists of. That is why we have prepared this article, with everything you need to know about S / PDIF.

Index of contents

What is the S / PDIF interface and what is it used for?

S / PDIF or SPDIF stands for Sony / Phillips Digital Interface, and is an interface for transmitting digital audio. In this article we explain everything you need to know about this interface, including when and how to use it. Digital Audio means that the audio signal is transmitted encoded in a series of 0s and 1s instead of being transmitted in analogue format, making it more faithful since no noise will be added to the signal. Therefore, it is always better to stream audio in digital format.

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Currently, there are three consumer level interfaces to transmit audio in digital format: SPDIF HDMI and DisplayPort. SPDIF only transmits audio, but HMDI and DisplayPort also transmit digital video signal. Why should you use SPDIF? It is because not all audio / video equipment has an HDMI or DisplayPort output available. For example, a professional-grade CD player or MiniDisc drive will have an available SPDIF output, but neither of the other two, as this computer does not produce video, only audio. Also, SPDIF cables and connectors are very thin, while HDMI and DisplayPort cables and connectors are bulky as they have more cables inside.

If you are connecting two audio devices, you will most likely have to use SPDIF as the audio source probably does not have an HDMI connector. For example, connecting a pro-level CD player or MiniDisc unit to an amplifier, or a pro-level mixer that supports SPDIF. If one or both computers do not have a SPDIF connector, digital audio connection will not be possible, and you will have to connect them through a normal analog connection, through a pair of RCA cables. In addition, as we will see later, there are two types of consumer-level SPDIF connectors: coaxial (RCA) and optical (Toslink). If you have a professional CD player that only has a coaxial SPDIF output, and its audio receiver has only an optical SPDIF input, you won't be able to connect them to SPDIF.

Suppose you are trying to connect equipment to your home theater setup, which is the most common situation. In your home theater system setup, you have two main components, the TV and the audio receiver (amplifier). For obvious reasons, you want the video signal to go to the TV and the audio signal to go to the audio receiver.

If you only have a television, that is, you do not have a home theater receiver with several speakers around, your best connection will be HDMI, if it is compatible with your television and the equipment you want to connect to your television. In this way you will have both audio and digital video, the best possible scenario. If your audio / video or television source does not have an HDMI connector, you will need two sets of cables, one to connect the video to the television, using the best available video connection, and a SPDIF cable that connects the audio / video source to your audio receiver or your TV, if you don't have an audio receiver.

If the receiver on your home theater system cannot extract the audio from the HDMI connectors, then you will be prompted to use SPDIF cables to carry the digital audio. There are two possible configurations for this scenario. Instead of having only one cable from each audio / video source, we will now have two: the HDMI cable, which carries the video signal, and the SPDIF cable, which carries the audio signal. In this case, all audio and video sources are directly connected to the TV, and assuming the TV can extract the audio from its HDMI inputs and route it to the SPDIF output, you will use this SPDIF output to connect the TV to the audio receiver.. Devices that only generate audio (for example, CD players, MiniDisc decks, etc.) must be connected directly to the audio receiver. In this case, the selection of what equipment will be used will be made on the television, not on the audio receiver.

Different types of S / PDIF connections and their use on PC

There are two types of consumer-level SPDIF connections, coaxial and optical. The coaxial connection uses a mono RCA connector, usually painted orange, to facilitate differentiation from video connections using a similar connector.

The optical connection uses a square connector called Toslink. Some computers have both connectors; some have only one of them. SPDIF coaxial cable is a simple mono RCA cable, while optical SPDIF cable is fiber optic. There are two types of optical connector. The most common is square, but a 3.5mm optical connector is also available. This 3.5mm jack is the same size as a 3.5mm headphone jack and is commonly used in notebooks. There are also adapters to convert the normal square connector into a 3.5mm one.

Availability of ready-to-use SPDIF connectors will depend on the motherboard or notebook PC model. By looking at the back panel of your PC, you can easily see if it has optical and / or coaxial SPDIF connectors. On laptops, the presence of an SPDIF output is more difficult to detect, as it is generally paired with the headphone jack, which supports the 3.5mm optical jack. Therefore, most users think that they do not have SPDIF output on their laptops, while this feature may be available.

You should look around the headphone jack to see if the word "SPDIF" is written near it. However, several notebook models show no indication that they have SPDIF output. You'll need to check the product specification page to see if SPDIF is listed. If so, then the headphone jack is also an SPDIF output.

There are other tricks to detect support for SPDIF. You can try using your PC in the dark and playing a song with it to see if you can see a red light coming out of the headphone jack, indicating that there is an SPDIF interface inside. Another trick is to see the color of the connector. If it's just green, the connector probably doesn't have the SPDIF function, but if it's black, it probably does. Unfortunately, not all manufacturers follow this scheme.

Recommended S / PDIF cables

deleyCON 0.5m Optical Digital Audio Cable S / PDIF 2X Toslink Connector Fiber Optic Cable Metal Connector 5mm Flexible - Black 8.59 EUR Toslink Cable 2.5m ~ 24k gold plated ~ ~ Lead Optical Digital S / PDIF stereo ~ ~ Audio 7.85 EUR FosPower (3 ft / 0.9m 24K Gold Plated Toslink to Mini Toslink Digital optical S / PDIF Audio Cable Includes a limited lifetime warranty 9.99 EUR

This ends our article on the S / PDIF connection, we hope you find it very useful and have cleared all your doubts about this digital audio interface. Did you know about this connection? Have you used it on your PC or multimedia center?