peppermint wrote:That if it has one ring its mono and two rings its stereo )
That's not entirely the full truth - stereo often uses TRS connectors, but so does something called "balanced audio" which, in comparison to standard TS instrument cables (the normal guitar cables with just a tip and a sleeve, no third conductor), offers much higher rejection of electromagnetic interference and thus is used in professional gear for a cleaner signal and longer cable length without degradation of performance from interference.
You can also get stereo audio like the Nord keyboards do, with a pair of mono TS instrument cables (most pro gear does this with a pair of TRS balanced cables, each monophonic but carrying that fancy balanced signal).
So it's important to be able to distinguish between 'stereo TRS', a 'balanced TRS', and a mono TS aka 'instrument cable'. This has tripped a lot of people up before, so understanding the difference is worth it when you're starting out! The TRS cables themselves are exactly the same, the only difference is what the purpose of the connectors are on each end of the connection - if you plug a stereo device into a mono balanced input or vice versa, you won't get what you might expect unless you're aware that they're different uses for the same connector type and cable!
