diff --git a/src/mame/drivers/indy_indigo2.cpp b/src/mame/drivers/indy_indigo2.cpp
index 24853edc771..64a1f0c627c 100644
--- a/src/mame/drivers/indy_indigo2.cpp
+++ b/src/mame/drivers/indy_indigo2.cpp
@@ -341,7 +341,7 @@ READ32_MEMBER( ioc2_device::read )
 		case 0x34/4: // Serial Port1 Data Transfer
 		case 0x38/4: // Serial Port2 Command Transfer
 		case 0x3c/4: // Serial Port2 Data Transfer
-			return m_scc->ba_cd_r(space, (offset - 0x30/4) ^ 1);
+			return m_scc->ba_cd_r(space, (offset - 0x30/4) ^ 3);
 
 		case 0x40/4: // Keyboard/Mouse Registers
 		case 0x44/4: // Keyboard/Mouse Registers