diff --git a/c64/aliases/,aliases_ram_lowmem.s b/c64/aliases/,aliases_ram_lowmem.s
index 211b19e9..d821ffaf 100644
--- a/c64/aliases/,aliases_ram_lowmem.s
+++ b/c64/aliases/,aliases_ram_lowmem.s
@@ -104,9 +104,9 @@
 	.label PTR2      = $9F  //          -- NOT IMPLEMENTED --
 	.label TIME      = $A0  // $A0-$A2  jiffy clock
 #if !CONFIG_IEC_JIFFYDOS	
-	.label TSFCNT    = $A3  //          temporary variable for tape and IEC, [!] our usage probably differs in details
+	.label TSFCNT    = $A3  //          temporary variable for tape and IEC, [!] our usage differs
 #else
-	.label IECPROTO  = $A3  //          [!] 0 = normal, 1 = JiffyDOS, >= $80 for unknown
+	.label IECPROTO  = $A3  //          -- WIP -- [!] 0 = normal, 1 = JiffyDOS, >= $80 for unknown
 #endif
 	.label TBTCNT    = $A4  //          temporary variable for tape and IEC, [!] our usage probably differs in details
 	.label CNTDN     = $A5  //          -- NOT IMPLEMENTED --
@@ -162,8 +162,8 @@
 	.label LDTBL     = $D9  // $D9-$F2  screen line link table, [!] our usage is different  XXX give more details
 	.label USER      = $F3  // $F3-$F4  pointer to current color RAM location
 	.label KEYTAB    = $F5  // $F5-$F6  pointer to keyboard lookup table
-	.label RIBUF     = $F7  // $F7-$F8  -- NOT IMPLEMENTED -- (WIP)
-	.label ROBUF     = $F9  // $F9-$FA  -- NOT IMPLEMENTED -- (WIP)
+	.label RIBUF     = $F7  // $F7-$F8  -- WIP -- RS-232 receive buffer pointer
+	.label ROBUF     = $F9  // $F9-$FA  -- WIP -- RS-232 send buffer pointer
 	//                 $FB     $FB-$FE  -- UNUSED --          free for user software
 	.label BASZPT    = $FF  //          -- NOT IMPLEMENTED --
 
@@ -206,14 +206,14 @@
 	.label M51CRT    = $293  //            -- NOT IMPLEMENTED -- mock 6551
 	.label M51CDR    = $294  //            -- NOT IMPLEMENTED -- mock 6551
 	.label M51AJB    = $295  // $295-$296  -- NOT IMPLEMENTED -- mock 6551
-	.label RSSTAT    = $297  //            -- NOT IMPLEMENTED -- mock 6551, RS-232 status
+	.label RSSTAT    = $297  //            -- WIP -- mock 6551, RS-232 status
 	.label BITNUM    = $298  //            -- NOT IMPLEMENTED --
 	.label BAUDOF    = $299  // $299-$29A  -- NOT IMPLEMENTED --
 #endif
-	.label RIDBE     = $29B  //            -- NOT IMPLEMENTED -- (WIP)
-	.label RIDBS     = $29C  //            -- NOT IMPLEMENTED -- (WIP)
-	.label RODBS     = $29D  //            -- NOT IMPLEMENTED -- (WIP)
-	.label RODBE     = $29E  //            -- NOT IMPLEMENTED -- (WIP)
+	.label RIDBE     = $29B  //            -- WIP -- write pointer into RS-232 receive buffer
+	.label RIDBS     = $29C  //            -- WIP -- read pointer into RS-232 receive buffer
+	.label RODBS     = $29D  //            -- WIP -- read pointer into RS-232 send buffer
+	.label RODBE     = $29E  //            -- WIP -- write pointer into RS-232 send buffer
 	.label IRQTMP    = $29F  // $29F-$2A0  -- NOT IMPLEMENTED --
 	.label ENABL     = $2A1  //            -- NOT IMPLEMENTED --
 	.label TODSNS    = $2A2  //            -- NOT IMPLEMENTED --
@@ -282,5 +282,8 @@
 	//                 $314     $334-$33B  -- UNUSED --          free for user software
 	
 	.label TBUFFR    = $33C  // $33C-$3FB  [!] tape buffer, our usage details differ
+#if CONFIG_RS232_UP9600
+    .label REVTAB    = $37C  // $37C-$3FB  -- WIP -- [!] RS-232 precalculated data
+#endif
 
 	//                 $3FC     $3FC-$3FF  -- UNUSED --          free for user software
diff --git a/c64/kernal/rs232/chrin_rs232.s b/c64/kernal/rs232/chrin_rs232_up2400.s
similarity index 54%
rename from c64/kernal/rs232/chrin_rs232.s
rename to c64/kernal/rs232/chrin_rs232_up2400.s
index 7c39d342..252cf2db 100644
--- a/c64/kernal/rs232/chrin_rs232.s
+++ b/c64/kernal/rs232/chrin_rs232_up2400.s
@@ -1,14 +1,14 @@
 
 //
-// RS-232 part of the CHKRIN routine
+// RS-232 part of the CHRIN routine
 //
 
 
-#if HAS_RS232
+#if CONFIG_RS232_UP2400
 
 
 chrin_rs232:
 	STUB_IMPLEMENTATION() // XXX provide implementation for both UP2400 and UP9600
 
 
-#endif // HAS_RS232
+#endif // CONFIG_RS232_UP2400
diff --git a/c64/kernal/rs232/chrin_rs232_up9600.s b/c64/kernal/rs232/chrin_rs232_up9600.s
new file mode 100644
index 00000000..eb39f003
--- /dev/null
+++ b/c64/kernal/rs232/chrin_rs232_up9600.s
@@ -0,0 +1,43 @@
+
+//
+// RS-232 part of the CHRIN routine
+//
+
+// Based on UP9600 code by Daniel Dallman with Bo Zimmerman adaptations
+
+
+#if CONFIG_RS232_UP9600
+
+
+chrin_rs232:
+
+	phy_trash_a
+	phx_trash_a
+
+	lda #$00
+	sta XXX_SAVBYTE
+    sta RSSTAT
+	jsr XXX_RSIN
+    bcc !+
+	plx_trash_a
+	ply_trash_a
+	
+	lda #$08    // XXX don't we have some routine for this?
+	sta RSSTAT
+    lda #$00
+    clc
+    rts
+!:
+	sta XXX_SAVBYTE
+
+XXX_DOGET4:
+
+	plx_trash_a
+	ply_trash_a
+
+	lda XXX_SAVBYTE
+	clc
+	rts
+
+
+#endif // CONFIG_RS232_UP9600