Well, if you believe DIRECTV…
TOSLINK, otherwise known as optical audio, started life as “Toshiba Link,” a way for Toshiba-branded CD players to connect to audio systems. Of course this was back in 1983 when people cared about CD players, and back when you could buy something from Toshiba with a fairly straight face. It was one of the first formats to allow a purely digital transfer from one home theater device to another, and it was also one of the first formats to allow more than two channels on a single cable.
TOSLINK was not only reknowned, it was cool because it combined fiber and laser technologies in a way that 1980s kids thought reminded them of the future. It wasn’t perfect… even though fiber optics can go thousands of feet TOSLINK cables usually can’t because of cheap manufacturing. Still, TOSLINK was dominant well through the 1990s and 2000s.
And then, the coolness just couldn’t carry it anymore. Sony and Philips, both big names in their day, had a different standard: The Sony/Philips Digital Interchange Format, or S/PDIF. S/PDIF, or coaxial audio as it was more commonly called, used digital encoding over a plain old RCA cable to do the same thing that TOSLINK did with lasers and fiber optics. It may not have been as sexy, but it was usually cheaper to make after about 2005 when computer chips were able to process the signal easily. In the mid-2000s it was common for A/V equipment to have both TOSLINK and S/PDIF as choices, as both were relatively inexpensive.
And then, HDMI happened.
For consumers, HDMI was a dream come true — a single cable that carried HD video and enough audio channels for most people. Never mind the whole thing where HDMI is laden with copy protection features, it just didn’t matter. It took a few years for HDMI to really catch on but even audiophiles couldn’t deny the appeal of one digital cable instead of (up to) 9 analog RCA cables. HDMI also had a new feature called ARC (Audio Return Channel) where the sound could travel backwards from a TV to an audio receiver, making it even easier to connect.
When HDMI got its act together, the writing was on the wall for digital audio, and that’s when manufacturers like DIRECTV figured out that they didn’t always need to provide both types of outputs, especially when there were converters to go from S/PDIF to TOSLINK or TOSLINK to S/PDIF available at very low prices. Starting in about 2010, DIRECTV phased out TOSLINK on some devices to save space and cost, and most of the company’s products don’t have TOSLINK to this day. HDMI switching does the heavy lifting now, and most consumers don’t mind.
In the meantime, both TOSLINK and S/PDIF aren’t capable of carrying the new digital audio formats like Dolby Atmos that are really exciting to audiophiles, so those folks have left those cables back in the 1980s where they probably belong. There are a few products like soundbars that still work off TOSLINK so it’s not completely obsolete, but let’s be honest… the writing is on the wall.