diff --git a/Source/HBIOS/std.asm b/Source/HBIOS/std.asm
index 6ee025ce..47fd8d2e 100644
--- a/Source/HBIOS/std.asm
+++ b/Source/HBIOS/std.asm
@@ -1053,14 +1053,14 @@ INT_PIO1B	.EQU	12	; ZILOG PIO 1, CHANNEL B
 ;
 ; NABU Z80 IM2 INTERRUPTS
 ;
-INT_HCAARCV	.EQU	0	; UART 0
-INT_HCAASND	.EQU	1	; UART 1 ?????
-INT_NABUKB	.EQU	2	; ZILOG CTC 0, CHANNEL A
-INT_VDP		.EQU	3	; ZILOG CTC 0, CHANNEL B
-INT_OPTCRD0	.EQU	4	; ZILOG CTC 0, CHANNEL C
-INT_OPTCRD1	.EQU	5	; ZILOG CTC 0, CHANNEL D
-INT_OPTCRD2	.EQU	6	; ZILOG SIO 0, CHANNEL A & B
-INT_OPTCRD3	.EQU	7	; ZILOG SIO 1, CHANNEL A & B
+INT_HCCARCV	.EQU	0	; CABLE ADAPTER RECEIVE
+INT_HCCASND	.EQU	1	; CABLE ADAPTER SEND
+INT_NABUKB	.EQU	2	; KEYBOARD RECEIVE
+INT_VDP		.EQU	3	; VDP VERTICAL RETRACE
+INT_OPTCRD0	.EQU	4	; OPTION CARD 0
+INT_OPTCRD1	.EQU	5	; OPTION CARD 1
+INT_OPTCRD2	.EQU	6	; OPTION CARD 2
+INT_OPTCRD3	.EQU	7	; OPTION CARD 3
 
   #ENDIF