I have bought a new headset that has a 3-pin audio jack port. The cable that came with it has 3-pin audio jack 3.5 (I think its also called AUX?) on both sides. Would it be safe to plug it into 4-pin audio port in the laptop or the phone?
EDIT: It is a stereo headphone (output) with a mic (input). It works both via Bluetooth as well as a 3-pin audio jack cable.
Generally, yes, such ports are designed to work with regular 3-pin headphone jacks as well as 4-pin headset jacks. The phone or laptop will automatically detect what kind of device is connected.
Physically both are compatible, as the "ring" of a 3-pin TRS jack is always at the same position as on a 4-pin TRRS one, and phones and laptops usually detect whether the "sleeve" is a single contact or split into ground+mic.
(These days phones even detect the two possible wirings of TRRS jacks. It's similar to how all modern PCs have been able to guess speakers and mics even if connected to the wrong port.)
It's the opposite, a 4-pin jack inside a 3-pin port, that has a risk of not aligning correctly.
However, this is for 3-pin stereo headphone jacks. If you have something else, such as mono headset with microphone (do those exist?), it still will not damage anything but probably won't work.
