Looks like you have one of these (or a close variant) Anchor Electronics - Media Concept 2.0 Souncard - SB 2.0 clone with real OPL2

If you are a looking for an input to connect your motherboard's PC speaker out, I'm afraid there isn't one .

Thank You

The original CT1350 Have it?

Or how can i plug it to line in?

Sadly many dos game run without possibility ro change audio device from speaker to sb

CT1600 has one. I checked my CT1350B and it doesn't have it.

Thank you

The top port on that card is the Line In port, but I don't recommend using it. I recently reversed the Sound Blaster 2.0 CT1350B card that your card there is based on and my understanding is that it that treats the Line-In as mono audio, so it would probably make stereo audio into mono.

And yeah, this card doesn't support managing the PC speaker in any way. That's a pretty nice feature on the SB16

Thermalwrong wrote on 2022-10-07, 15:38:

The top port on that card is the Line In port, but I don't recommend using it. I recently reversed the Sound Blaster 2.0 CT1350B card that your card there is based on and my understanding is that it that treats the Line-In as mono audio, so it would probably make stereo audio into mono.

And yeah, this card doesn't support managing the PC speaker in any way. That's a pretty nice feature on the SB16

Also, pre-SBPro cards don't have a controllable mixer, so anything fed to line-in likely won't be heard, unless the card is hard-wired to "mix" line-in with DAC output, which I don't know.

EDIT: The original Sound Blasters (pre Pro) do not output line-in through the speaker out . Sound Blaster 2.0 (CT1350B) line in not working.

From what I recall, it's really just routed into the mic input but with less amplification