40 pin IDC male connector at the soundcard.
The AUD_EXT connector is a proprietary 2×20-pin (40-pin) IDC ribbon-cable header fitted to Creative Sound Blaster Live! cards of the EMU10K1 era (circa 1998–2002). It connects the PCI sound card to front-panel accessories such as the Live! Drive IR or an Optical Digital I/O card mounted in a 5.25-inch drive bay. The header carries S/PDIF digital audio streams, I2S audio data, MIDI signals, a 24.5 MHz AC97 clock, and power lines. Creative’s proprietary ribbon cable is not interchangeable with a standard IDE ribbon cable; substituting one risks electrical damage to the card and connected drive.
| 1 | VCC | +5V power supply |
| 2 | VCC | +5V power supply |
| 3 | GND | Ground |
| 4 | AC97CLK | 24.5 MHz clock output |
| 5 | GND | Ground |
| 6 | GP_SPDIFIN#2 | SPDIF input signal |
| 7 | GND | Ground |
| 8 | GND | Ground |
| 9 | SPDIFO#3 | SPDIF Out signal |
| 10 | GPO1 | General Purpose Output #1 |
| 11 | GPO2 | General Purpose Output #2 |
| 12 | GND | Ground |
| 13 | GPO0 | General Purpose Output #0 |
| 14 | GND | Ground |
| 15 | GP_SPDIFIN1 | SPDIF Input signal |
| 16 | GND | Ground |
| 17 | SPDIFO#0 | SPDIF Out signal |
| 18 | GND | Ground |
| 19 | SPDIFO#1 | SPDIF Out signal |
| 20 | GND | Ground |
| 21 | GND | Ground |
| 22 | SPDIFO#2 | SPDIF Out signal |
| 23 | GPI0 | Digital Input (GP Input 0; Reserved) |
| 24 | GPI1 | Digital Input, (GP Input 1; Reserved) |
| 25 | OUTMIDI | MIDI Output |
| 26 | GND | Ground |
| 27 | INMIDI | MIDI Input |
| 28 | GND | Ground |
| 29 | KEY | |
| 30 | KEY | |
| 31 | ADCSDO2 | I2S audio data input. |
| 32 | GND | Ground |
| 33 | ADCSDO1 | I2S audio data input. |
| 34 | GND | Ground |
| 35 | ADCSDO0 | I2S audio data input. |
| 36 | GND | Ground |
| 37 | I2SCLK | I2S serial bit clock. |
| 38 | GND | Ground |
| 39 | I2SFS | Frame sync. |
| 40 | GND | Ground |
Notes
- ADC = Analog-to-Digital Converter
- Pins 29 and 30 are keying positions (absent pin); they prevent incorrect cable orientation.
- The AUD_EXT cable is a dark grey flat ribbon cable supplied by Creative. It must not be replaced with a standard 40-pin IDE ribbon cable, as the signal assignments differ and a substitution risks permanent damage to the card and drive bay accessory.
- The connector is present on Sound Blaster Live! cards (EMU10K1 chipset). Later Audigy and X-Fi cards use a functionally similar but renamed AD_EXT header.
Signals
- VCC — +5 V power supply to the connected drive bay accessory (pins 1–2)
- GND — Ground reference (multiple pins)
- AC97CLK — 24.5 MHz serial clock output for AC97-compatible audio codec synchronisation
- GP_SPDIFIN#2 — S/PDIF digital audio input (general-purpose path 2)
- SPDIFO#0–#3 — S/PDIF digital audio output channels 0 through 3
- GPO0–GPO2 — General-purpose digital outputs; used for control signalling to the drive bay
- GP_SPDIFIN1 — S/PDIF digital audio input (general-purpose path 1)
- GPI0, GPI1 — General-purpose digital inputs; reserved
- OUTMIDI — MIDI data output
- INMIDI — MIDI data input
- ADCSDO0–ADCSDO2 — I2S audio data inputs from the ADC (analogue-to-digital converter) in the drive bay
- I2SCLK — I2S serial bit clock
- I2SFS — I2S frame sync (word-select / left-right clock)