It's just another name for the SB_Link connector, which you can find on a lot of PIII motherboards.

And yeah, you could consider it a sort of 'fake ISA' in a way, it's a link that provides the DMA and IRQ signals from the ISA bus, which isn't present in the PCI bus.

I used the SB-Link connection succesfully with two Waveforce XG clones (same chipset, different soundcard). The cards could also do SB-Pro emulation without the cable attached though. Another PCI chipset that supports the SB-Link connector is the ESS Solo-1, as used on Terratec budget soundcards.

I understood SB-Link was initially proposed by Creative Labs, hence the name Sound Blaster Link:

Wikipedia wrote:

The AWE64 came in three versions initially: A "Value" version (with 512KB of RAM), a standard version (with 1 MB of RAM), and a "Gold" version (with 4 MB of RAM, high quality 20bit DAC and a separate SPDIF output).

A fourth version that arrived later was designed around the PCI bus. It offers the features of the original ISA AWE64, but it has the PCI interface and is built around an even more integrated ASIC. This made the board even more compact, and thus cheaper to build. Unfortunately, during this card's time, the issue of compatibility with older legacy DOS applications accessing PCI audio cards had not been ideally addressed. Creative created a motherboard port called the "SB-Link" that assisted the PCI bus in working with software that looked for the legacy I/O resources of ISA sound cards. Without this motherboard port, the card was incompatible with DOS software.