Don't recognize it, so I can't help too much, but seeing the sticker on the back (where it says Artsound P2), it originally seems to have been in a German system or from a German seller at least (which rather disqualifies my first idea of maybe being from a DEL(L) system).

ildonaldo wrote on 2022-08-27, 13:01:

Can you help to identify this card and assign the i/o ports?

You can get the data sheet for the ES688 sound chip, which includes information about the configuration pins. Following the traces on the card results in:

JP1/JP8: base I/O select (220: open/open; 230: open/1-2; 240: 1-2/open; 250: 1-2/1-2)
JP2: interrupt select (IRQ2/9: open; IRQ5: 3-4; IRQ7: 1-2; IRQ10: 1-2 & 3-4)
JP3: DMA select (no DMA: open; DMA0: 3-4; DMA1: 1-2; DMA3: 1-2 & 3-4)

Your card is jumpered to the usual settings for soundblaster compatible cards: A220 I5 D1.

It's not the internal settings I am worried about (cause unchanged), but I wouldn't like to fry the internal amplifier of the case by connecting it to the wrong Output.

MJay99 wrote on 2022-08-27, 13:42:

Don't recognize it, so I can't help too much, but seeing the sticker on the back (where it says Artsound P2), it originally seems to have been in a German system or from a German seller at least (which rather disqualifies my first idea of maybe being from a DEL(L) system).

The original system is the german brand "Palladium" but not Dell, so it is probably some OEM Card.

ildonaldo wrote on 2022-08-27, 15:03:

It's not the internal settings I am worried about (cause unchanged), but I wouldn't like to fry the internal amplifier of the case by connecting it to the wrong Output.

OK, sorry. When you set "I/O ports", I was immediately thinking about ISA I/O port addresses, that's why I focussed on the wrong topic. I hope this answer is more helpful:

The jack between the the joystick port is speaker out for sure. You can easily identify "speaker out" by the pair of big elecrolytic caps connected directly to the output jack pins and the LM1877 speaker amplifier chip. The capacitors are the DC decoupling caps, and you only need such big caps if a device requiring some power (like headphones or even small unpowered speakers) are connected. This card had no unamplified "line out" jack, as is typical for old PC sound cards with a volume pot.

The jack directly adjacent to the volume pot on the other side is "line in". You can recognize that, because that jack has a stereo wiring: C7/R6 and C6/R12 are identical, one is connected to the right channel, and one is connected to the left channel. This input likely goes directly into the ES688 chip.

The top jack is "microphone input". You can recognize it by not having identically wired left/right channels. Another clue for this channel being "microphone" is the KA3403 chip, which is a simple general-purpose amplifier chip used to boost the microphone signal, which seems to be connected to the signal from this jack.

Oh dear, so it's only an "speaker out", "line in" and "microphone input" - I have ben asking because another vogon fellow just told my to be cautious with the ouput lines not to fry the internal amplifier ...

ildonaldo wrote on 2022-08-27, 18:54:

Oh dear, so it's only an "speaker out", "line in" and "microphone input" - I have ben asking because another vogon fellow just told my to be cautious with the ouput lines not to fry the internal amplifier ...

If you connect speaker out to the amplifier input, you can easily cause distortion due to overdriving the audio amplifier of that case. Actual damage is less likely, but I can't exclude the possibility. Turning the volume pot down (test with headphones which end is "soft" and which end is "loud") before adding the TRS cable connecting "speaker out" of the ESS688 card to the audio amplifier, and then carefully increasing it until you get a decent sound level should avoid the remaining risk of causing damage.

Stupid me 😉
Test first with Headset, then connect - sometimes it is that simple ...