IIRC, there are two connections that need to be made between the box and the card, one is FireWire and the other uses a special connector. They are labelled ADATA1 and ADATA2.

I assume that power is delivered over the FireWire. If you connect only the "floppy connector" as you call it then the unit will not get power.

I attached both cables to the box.

OK, you are right. This is the setup:

Computer PSU -> floppy power cable -> Audigy card -> AD_LINK1/AD_LINK2 cables -> box

Driver is correct. The remote is not important. The power LED on the box should light up if everything is connected correctly.

Hi @RaiderOfLostVoodoo. I have a Audigy 4 Pro, quite similar to your 2 ZS. The external module works fine without the FireWire 400 plugged-in anyway. But as both cables are attached together, there is no reason to not plug them both.
I don't think your problem comes from here, but it is good to do as having problems with the connectors is very common. So I recommend you to first clean up the connectors, on the cable, on the sound card and on the module. The plug of the connector is very fragile with tiny slats and a very thin socket. So first thing to check is that nothing is damaged here. Then use contact cleaner and with a small brush, gently rub the contacts (on hardware and cable plugs). I know contacts are gold plated, but the gold is only on a very small thickness, so it can be corroded if damaged (scratches due to insertion and removal). Once done, insert firmly the cable on both AD_LINK1 ends until it click. After that, nothing should have changed, but you are on a good basis for the rest.
Yes, you need to use the Berg connector to deliver power to the module through the sound card.
The module is passive. By that, I mean it is not a plug and play device detected by OS. From the card point of view having the module connected or not change nothing. The card act exactly the same, but if the module is connected, that just allow data to pass from/to the card. Think of a sound card line out / line in / Mic connectors but with added MIDI, Digital audio data, and digital proprietary bus for infrared and volume control. That's all what it is. So your "Unknown device" is, I think, not related to the module but probably to a driver or resource issue. First go here [https://support.creative.com/Products/Product … e=Sound+Blaster], you will find the doc and the drivers. Install the version 2.18.0017. If nothing changes, you can try to put the card in a different PCI slot. I do not use my card this days, but if I remember well, the power LED on the module is not really a power LED, but more a Link enabled LED. It should lit on only if the driver has enable the chip in charge of the communications on the card so if the module is plugged in the LED indicate it can communicate with the card. If after that you still got no success, let us know for further help.
Hope to help you.

Sadly I ran out of Isopropanol a week ago. I only have canned air, which I tried.

The unknown device is definitely related to the Audigy, as it disappears when I remove the card.
It now got identified as a Creative Game Port. The Audigy doesn't even have one?!? After a restart it was gone again.
It still appears, when the box is detached. So it's linked to the card itself and not the box.

Still no sign of life from the box. Windows tells me, there are no headphones attached.

RaiderOfLostVoodoo wrote on 2021-11-13, 16:42:

Sadly I ran out of Isopropanol a week ago. I only have canned air, which I tried. […]
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Sadly I ran out of Isopropanol a week ago. I only have canned air, which I tried.

The unknown device is definitely related to the Audigy, as it disappears when I remove the card.
It now got identified as a Creative Game Port. The Audigy doesn't even have one?!? After a restart it was gone again.
It still appears, when the box is detached. So it's linked to the card itself and not the box.

Still no sign of life from the box. Windows tells me, there are no headphones attached.

Some Audidy cards have a bracket with a game port on it, it is plugged on the card. I'm pretty sure my Audigy 4 Pro does not have one as USB game controller where the de-facto standard when it was release, but your 2 ZS Platinum Pro should have one if I remember. I have an Audigy 2 ZS Platinum on a machine but I do not have installed the bracket. The difference between the Platinum and the Platinum Pro is that one have an internal rack and the other have the external module. I don't remember any other differences. I have a Live! 5.1 Platinum too with the second version of the rack, it is the same rack as the Audigy 2 ZS, but in black. Maybe the PCB is of a different revision, I haven't check that. But I am pretty sure the external module of the 2 ZS Platinum Pro is the same as the Audigy 4 Pro.
That is what is wonderful with Creative Labs. They are just collectible because there is a huge number of products having a huge number of revisions. Gotta Catch 'Em All is almost impossible.

Edit: That is not related to the thread, but I made an error, so I correct it. I just checked today on the two PCs, the rack for the Audigy 2 ZS have a FireWire port added compared to the one of the Live! 5.1, and it is not just a port, the FW plug is on the PCB so the PCB is different. I totally forgot the FireWire ! And there is a difference and term of functionality between a Audigy 2 ZS Platinum and Platinum Pro: with the module it is possible to enable CMSS with a dedicated button. With the rack version, it can only be done by the remote control or by software and there is no LED to tell if it is enabled or not.