diff --git a/apps/telnet65.s b/apps/telnet65.s
index db3afb2..c20412b 100644
--- a/apps/telnet65.s
+++ b/apps/telnet65.s
@@ -3,6 +3,7 @@
 .include "../inc/common.i"
 .include "../inc/commonprint.i"
 .include "../inc/net.i"
+.include "../inc/error.i"
 
 .export start
 
diff --git a/inc/common.i b/inc/common.i
index 6b36d61..73b8219 100644
--- a/inc/common.i
+++ b/inc/common.i
@@ -1,7 +1,3 @@
-.ifndef COMMON__I__
-
-COMMON__I__ = 1
-
 ; load A/X macro
 .macro ldax arg
 .if (.match (.left (1, arg), #))      ; immediate mode
@@ -42,8 +38,6 @@ COMMON__I__ = 1
   pla
 .endmacro
 
-.endif
-
 
 
 ; -- LICENSE FOR common.i --
diff --git a/inc/commonprint.i b/inc/commonprint.i
index 03bbdbf..198c287 100644
--- a/inc/commonprint.i
+++ b/inc/commonprint.i
@@ -2,11 +2,7 @@
   SCREEN_WIDTH = 40
 .endif
 
-.ifndef KPR_API_VERSION_NUMBER
-  .define EQU =
-  .include "zeropage.inc"
-  .include "../inc/kipper_constants.i"
-.endif
+.include "zeropage.inc"
 
 .export print_hex
 .export print_ip_config
diff --git a/inc/error.i b/inc/error.i
new file mode 100644
index 0000000..f22fb14
--- /dev/null
+++ b/inc/error.i
@@ -0,0 +1,33 @@
+KPR_ERROR_PORT_IN_USE                   = $80
+KPR_ERROR_TIMEOUT_ON_RECEIVE            = $81
+KPR_ERROR_TRANSMIT_FAILED               = $82
+KPR_ERROR_TRANSMISSION_REJECTED_BY_PEER = $83
+KPR_ERROR_INPUT_TOO_LARGE               = $84
+KPR_ERROR_DEVICE_FAILURE                = $85
+KPR_ERROR_ABORTED_BY_USER               = $86
+KPR_ERROR_LISTENER_NOT_AVAILABLE        = $87
+KPR_ERROR_CONNECTION_RESET_BY_PEER      = $89
+KPR_ERROR_CONNECTION_CLOSED             = $8A
+KPR_ERROR_MALFORMED_URL                 = $A0
+KPR_ERROR_DNS_LOOKUP_FAILED             = $A1
+
+
+
+; -- LICENSE FOR error.i --
+; The contents of this file are subject to the Mozilla Public License
+; Version 1.1 (the "License"); you may not use this file except in
+; compliance with the License. You may obtain a copy of the License at
+; http://www.mozilla.org/MPL/
+;
+; Software distributed under the License is distributed on an "AS IS"
+; basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See the
+; License for the specific language governing rights and limitations
+; under the License.
+;
+; The Original Code is ip65.
+;
+; The Initial Developer of the Original Code is Jonno Downes,
+; jonno@jamtronix.com.
+; Portions created by the Initial Developer are Copyright (C) 2009
+; Jonno Downes. All Rights Reserved.
+; -- LICENSE END --
diff --git a/inc/kipper_constants.i b/inc/kipper_constants.i
deleted file mode 100644
index 85cff1e..0000000
--- a/inc/kipper_constants.i
+++ /dev/null
@@ -1,39 +0,0 @@
-; constants for accessing the KPR API file
-; to use this file under CA65 add ".define EQU =" to your code before this file is included.
-
-KPR_API_VERSION_NUMBER EQU $01
-
-; error codes (as returned by KPR_GET_LAST_ERROR)
-KPR_ERROR_PORT_IN_USE                   EQU $80
-KPR_ERROR_TIMEOUT_ON_RECEIVE            EQU $81
-KPR_ERROR_TRANSMIT_FAILED               EQU $82
-KPR_ERROR_TRANSMISSION_REJECTED_BY_PEER EQU $83
-KPR_ERROR_INPUT_TOO_LARGE               EQU $84
-KPR_ERROR_DEVICE_FAILURE                EQU $85
-KPR_ERROR_ABORTED_BY_USER               EQU $86
-KPR_ERROR_LISTENER_NOT_AVAILABLE        EQU $87
-KPR_ERROR_CONNECTION_RESET_BY_PEER      EQU $89
-KPR_ERROR_CONNECTION_CLOSED             EQU $8A
-KPR_ERROR_MALFORMED_URL                 EQU $A0
-KPR_ERROR_DNS_LOOKUP_FAILED             EQU $A1
-
-
-
-; -- LICENSE FOR kipper_constants.i --
-; The contents of this file are subject to the Mozilla Public License
-; Version 1.1 (the "License"); you may not use this file except in
-; compliance with the License. You may obtain a copy of the License at
-; http://www.mozilla.org/MPL/
-;
-; Software distributed under the License is distributed on an "AS IS"
-; basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See the
-; License for the specific language governing rights and limitations
-; under the License.
-;
-; The Original Code is ip65.
-;
-; The Initial Developer of the Original Code is Jonno Downes,
-; jonno@jamtronix.com.
-; Portions created by the Initial Developer are Copyright (C) 2009
-; Jonno Downes. All Rights Reserved.
-; -- LICENSE END --
diff --git a/ip65/dhcp.s b/ip65/dhcp.s
index 4e18525..afd97f9 100644
--- a/ip65/dhcp.s
+++ b/ip65/dhcp.s
@@ -10,11 +10,7 @@
 MAX_DHCP_MESSAGES_SENT = 12     ; timeout after sending 12 messages will be about 15 seconds (1+2+3...)/4
 
 .include "../inc/common.i"
-
-.ifndef KPR_API_VERSION_NUMBER
-  .define EQU =
-  .include "../inc/kipper_constants.i"
-.endif
+.include "../inc/error.i"
 
 .export dhcp_init
 .import dhcp_server
diff --git a/ip65/dns.s b/ip65/dns.s
index d4c4f83..95f1c7d 100644
--- a/ip65/dns.s
+++ b/ip65/dns.s
@@ -4,11 +4,7 @@ MAX_DNS_MESSAGES_SENT = 8       ; timeout after sending 8 messages will be about
 
 .include "zeropage.inc"
 .include "../inc/common.i"
-
-.ifndef KPR_API_VERSION_NUMBER
-  .define EQU =
-  .include "../inc/kipper_constants.i"
-.endif
+.include "../inc/error.i"
 
 .export dns_set_hostname
 .export dns_resolve
diff --git a/ip65/http.s b/ip65/http.s
index 60624b9..3ad9f8a 100644
--- a/ip65/http.s
+++ b/ip65/http.s
@@ -6,11 +6,6 @@
 .include "zeropage.inc"
 .include "../inc/common.i"
 
-.ifndef KPR_API_VERSION_NUMBER
-  .define EQU =
-  .include "../inc/kipper_constants.i"
-.endif
-
 .export http_parse_request
 .export http_get_value
 
diff --git a/ip65/httpd.s b/ip65/httpd.s
index 647d19a..02472b2 100644
--- a/ip65/httpd.s
+++ b/ip65/httpd.s
@@ -3,11 +3,7 @@
 
 .include "zeropage.inc"
 .include "../inc/common.i"
-
-.ifndef KPR_API_VERSION_NUMBER
-  .define EQU =
-  .include "../inc/kipper_constants.i"
-.endif
+.include "../inc/error.i"
 
 HTTPD_TIMEOUT_SECONDS = 5       ; what's the maximum time we let 1 connection be open for?
 
diff --git a/ip65/icmp.s b/ip65/icmp.s
index 2d9df17..73d9533 100644
--- a/ip65/icmp.s
+++ b/ip65/icmp.s
@@ -1,11 +1,7 @@
 ; ICMP implementation
 
 .include "../inc/common.i"
-
-.ifndef KPR_API_VERSION_NUMBER
-  .define EQU =
-  .include "../inc/kipper_constants.i"
-.endif
+.include "../inc/error.i"
 
 .export icmp_init
 .export icmp_process
diff --git a/ip65/ip65.s b/ip65/ip65.s
index 7f4d1ee..b13b732 100644
--- a/ip65/ip65.s
+++ b/ip65/ip65.s
@@ -1,11 +1,7 @@
 ; ip65 main routines
 
 .include "../inc/common.i"
-
-.ifndef KPR_API_VERSION_NUMBER
-  .define EQU =
-  .include "../inc/kipper_constants.i"
-.endif
+.include "../inc/error.i"
 
 .export ip65_init
 .export ip65_process
diff --git a/ip65/parser.s b/ip65/parser.s
index f11abaf..3ee49f4 100644
--- a/ip65/parser.s
+++ b/ip65/parser.s
@@ -8,11 +8,6 @@
 .include "zeropage.inc"
 .include "../inc/common.i"
 
-.ifndef KPR_API_VERSION_NUMBER
-  .define EQU =
-  .include "../inc/kipper_constants.i"
-.endif
-
 target_string = ptr1
 search_string = ptr2
 
diff --git a/ip65/sntp.s b/ip65/sntp.s
index c86e5c8..94e9c66 100644
--- a/ip65/sntp.s
+++ b/ip65/sntp.s
@@ -3,11 +3,7 @@
 MAX_SNTP_MESSAGES_SENT = 8
 
 .include "../inc/common.i"
-
-.ifndef KPR_API_VERSION_NUMBER
-  .define EQU =
-  .include "../inc/kipper_constants.i"
-.endif
+.include "../inc/error.i"
 
 .export sntp_ip
 .export sntp_utc_timestamp
diff --git a/ip65/tcp.s b/ip65/tcp.s
index 3b3dfa1..2044bd5 100644
--- a/ip65/tcp.s
+++ b/ip65/tcp.s
@@ -9,11 +9,7 @@ MAX_TCP_PACKETS_SENT = 8        ; timeout after sending 8 messages will be about
 
 .include "zeropage.inc"
 .include "../inc/common.i"
-
-.ifndef KPR_API_VERSION_NUMBER
-  .define EQU =
-  .include "../inc/kipper_constants.i"
-.endif
+.include "../inc/error.i"
 
 .import ip65_error
 
diff --git a/ip65/tftp.s b/ip65/tftp.s
index 95af5cf..dcb86a1 100644
--- a/ip65/tftp.s
+++ b/ip65/tftp.s
@@ -6,11 +6,7 @@ TFTP_TIMER_MASK  = $F8          ; mask lower two bits, means we wait for 8 x1/4
 
 .include "zeropage.inc"
 .include "../inc/common.i"
-
-.ifndef KPR_API_VERSION_NUMBER
-  .define EQU =
-  .include "../inc/kipper_constants.i"
-.endif
+.include "../inc/error.i"
 
 .export tftp_load_address
 .export tftp_ip
diff --git a/ip65/udp.s b/ip65/udp.s
index 6563a33..b19e83c 100644
--- a/ip65/udp.s
+++ b/ip65/udp.s
@@ -1,11 +1,7 @@
 ; UDP (user datagram protocol) functions
 
 .include "../inc/common.i"
-
-.ifndef KPR_API_VERSION_NUMBER
-  .define EQU =
-  .include "../inc/kipper_constants.i"
-.endif
+.include "../inc/error.i"
 
 .import ip65_error
 
diff --git a/ip65/url.s b/ip65/url.s
index 84cf946..81b92b3 100644
--- a/ip65/url.s
+++ b/ip65/url.s
@@ -2,11 +2,7 @@
 
 .include "zeropage.inc"
 .include "../inc/common.i"
-
-.ifndef KPR_API_VERSION_NUMBER
-  .define EQU =
-  .include "../inc/kipper_constants.i"
-.endif
+.include "../inc/error.i"
 
 TIMEOUT_SECONDS = 15