This is a Toslink icon. We've made it in iOS style, first introduced in iOS version 7 and supported in all later releases up until now (at least iOS 11). This style is based on thin two-pixel lines and is optimized for 50x50 px. Unlike other vector icon packs that have merely hundreds of icons, this icon pack contains 12,300 icons, all in the same style and quality.
The icon is a picture of the connector Toslink. The icon is a cylindrical shape with a rectangle extending out of it. There is a flat head needle coming out of the rectangle. The other end has a wire attached to it.