diff --git a/doc/hardware/bio2-sub-io-turntable-bypass-cable.md b/doc/hardware/bio2-sub-io-turntable-bypass-cable.md
new file mode 100644
index 0000000..92d41ec
--- /dev/null
+++ b/doc/hardware/bio2-sub-io-turntable-bypass-cable.md
@@ -0,0 +1,54 @@
+# BIO2 sub IO turntable bypass cable
+If you upgraded a C02/IO2 wired cabinet, the turntables are connected to the
+sub IO via a serial line that goes to another sub IO behind the front panel
+next to the 16seg display. This introduces additional latency as the input
+data needs to pass through multiple systems/PCBs until it reaches the game.
+
+This can be reduced by using a so-called "bypass" cable, that connects the
+turntables directly to the BIO2 sub IO board reducing latency significantly.
+
+This cable could be ordered with any IIDX upgrade kit including the BIO sub IO
+board but can also be easily created from scratch.
+
+## Parts
+* Some wires
+* [JST HL](https://jst.de/file/download/219/pitch-3-96-mm-wtw-hl2-pdf) 2x4 pin female connector
+* [JST HVQ](https://jst.de/file/download/637/hvq) 8 pin female connector
+* Matching terminals for the connectors
+
+## Pinout
+```text
+JST HL 2x4 pin front view connector
+
+notch at top
+    ___
+|---------|
+| 1 2 3 4 |
+| 5 6 7 8 |
+|---------|
+```
+
+```
+JST HVQ 8 pin front view connector
+Numbering on connector matches
+
+   notch at top
+___________________
+-------------------
+|-----------------|
+| 1 2 3 4 5 6 7 8 |
+|-----------------|
+
+```
+
+Pins of the two connectors need to be connected like this:
+| JST HL 2x4 pin | JST 8 pin |
+|----------------|-----------|
+| 1              | 1         |
+| 2              | 1         |
+| 3              | 3         |
+| 4              | 2         |
+| 5              | 5         |
+| 6              | 4         |
+| 7              | 8         |
+| 8              | 8         |
\ No newline at end of file
diff --git a/doc/iidxhook/iidxhook9.md b/doc/iidxhook/iidxhook9.md
index 697eb0e..fae4d44 100644
--- a/doc/iidxhook/iidxhook9.md
+++ b/doc/iidxhook/iidxhook9.md
@@ -178,6 +178,9 @@ stuck, try a USB <-> COM dongle instead of using one of the COM ports of the
 mainboard.
 
 # Troubleshooting and FAQ
+## The turntable input feels laggy/delayed with my BIO2 + sub IO
+See the [this readme](hardware/bio2-sub-io-turntable-bypass-cable.md) for
+information about the bypass cable.
 
 ## The game does not run "well" (frame drops, drifting offsync etc)
 This can be related to various issues: