diff --git a/konami/io.md b/konami/io.md
index 63faf56..7c79d5f 100644
--- a/konami/io.md
+++ b/konami/io.md
@@ -26,15 +26,7 @@
 
 ## C02 IO
 
-* GEC02-PWB(A)A
-* PCB product: PN0000228708
-* case/metal housing: PN0000246977
-* case/box cover: PN0000246978
-* Interface to main PCB: USB 1.1
-* Compatible games: [C02](software/C02.md), [D01](software/D01.md), [E11](software/E11.md),
-[ECO](software/ECO.md), [FDD](software/FDD.md), [GLD](software/GLD.md), [HDD](software/HDD.md),
-[I00](software/I00.md), [JDJ](software/JDJ.md), [JDZ](software/JDZ.md), [KDZ](software/KDZ.md),
-[LDJ (only up to 24 included)](software/LDJ.md)
+[C02 IO](io/c02-io.md)
 
 ## D01 IO
 
diff --git a/konami/io/c02-io.md b/konami/io/c02-io.md
new file mode 100644
index 0000000..599f677
--- /dev/null
+++ b/konami/io/c02-io.md
@@ -0,0 +1,67 @@
+# C02 IO
+
+* GEC02-PWB(A)A
+* PCB product: PN0000228708
+* case/metal housing: PN0000246977
+* case/box cover: PN0000246978
+* Interface to main PCB: USB 1.1
+* Compatible games: [C02](../software/C02.md), [D01](../software/D01.md), [E11](../software/E11.md),
+[ECO](../software/ECO.md), [FDD](../software/FDD.md), [GLD](../software/GLD.md), [HDD](../software/HDD.md),
+[I00](../software/I00.md), [JDJ](../software/JDJ.md), [JDZ](../software/JDZ.md), [KDZ](../software/KDZ.md),
+[LDJ (only up to 24 included)](../software/LDJ.md)
+
+## C02/D01 IO RJ45 to DIN8 connector pinout
+
+This was created by using the [BIO2 sub IO board](../io.md#bio2-ldj-sub-io) to connect pre IIDX 25 cabinet
+hardware to the [BIO2 IO board](../io.md#bio2). The two connector types from different generation IO boards, RJ45
+on the [C02 IO](#c02-io) board and a round DIN8 connector on the [USBIO2](../io.md#usbio2) board are just
+different connectors to the same hardware on the BIO2 sub IO board.
+
+Therefore, any C02/D01 wired cabinet can be upgraded to IO2 wiring and vice versa by building
+a RJ45 -> DIN8 or DIN8 -> RJ45 adapter cable.
+
+The following connection information was traced on a original Konami BIO2 sub IO board.
+
+RJ45 (female) connector, top view:
+
+```text
+plug insert
+     |
+     |
+     v
+|-----------|
+|  Top view |
+|           |
+|   Pins    |    
+|   7 5 3 1 |
+|  8 6 4 2  |
+|-----------|
+```
+
+DIN8 (female) connector, top view:
+
+```text
+plug insert
+     |
+     |
+     v
+|-----------|
+|  Top view |
+|   Pins    |    
+|  3  1 2 6 |
+| 7 4 5 8 9 |
+|-----------|
+```
+
+The two connectors are interconnected on the PCB like this:
+
+| RJ45 pins | DIN8 pins |
+|-----------|-----------|
+| 1         | 1         |
+| 2         | 7         |
+| 3         | 4         |
+| 4         | 6         |
+| 5         | 5         |
+| 6         | 3         |
+| 7         | 2         |
+| 8         | 1         |