diff --git a/c64/kernal/listen.s b/c64/kernal/listen.s
index 53dbd21e..a71db073 100644
--- a/c64/kernal/listen.s
+++ b/c64/kernal/listen.s
@@ -3,5 +3,5 @@
 listen:
 
 	;; This trivial routine is documented in 'Compute's Mapping the Commodore 64', page 223
-	ora $20
-	jmp iec_tx_byte
+	ora #$20
+	jmp iec_tx_byte ;; XXX add special routine for commands
diff --git a/c64/kernal/second.s b/c64/kernal/second.s
index 09ff93bb..a4dbb58f 100644
--- a/c64/kernal/second.s
+++ b/c64/kernal/second.s
@@ -2,5 +2,5 @@
 second:
 
 	;; This trivial routine is documented in 'C64 Programmer's Reference Guide', page 296
-	ora $60
+	ora #$60
 	jmp iec_tx_byte
diff --git a/c64/kernal/talk.s b/c64/kernal/talk.s
index a51faf8b..bd487e38 100644
--- a/c64/kernal/talk.s
+++ b/c64/kernal/talk.s
@@ -3,5 +3,5 @@
 talk:
 
 	;; This trivial routine is documented in 'Compute's Mapping the Commodore 64', page 223
-	ora $40
-	jmp iec_tx_byte
+	ora #$40
+	jmp iec_tx_byte ;; XXX add special routine for commands
diff --git a/c64/kernal/unlsn.s b/c64/kernal/unlsn.s
index c3854f7c..cdf99bc8 100644
--- a/c64/kernal/unlsn.s
+++ b/c64/kernal/unlsn.s
@@ -3,5 +3,5 @@
 unlsn:
 
 	;; This trivial routine is documented in 'Compute's Mapping the Commodore 64', page 224
-	lda $5F
-	jmp iec_tx_byte
+	lda #$5F
+	jmp iec_tx_byte ;; XXX add special routine for commands
diff --git a/c64/kernal/untlk.s b/c64/kernal/untlk.s
index 275adbaa..0fdc36c1 100644
--- a/c64/kernal/untlk.s
+++ b/c64/kernal/untlk.s
@@ -3,5 +3,5 @@
 untlk:
 
 	;; This trivial routine is documented in 'Compute's Mapping the Commodore 64', page 224
-	lda $5F
-	jmp iec_tx_byte
+	lda #$5F
+	jmp iec_tx_byte ;; XXX add special routine for commands