diff --git a/azbox/dmx_lib.h b/azbox/dmx_lib.h
index ed38048..754511e 100644
--- a/azbox/dmx_lib.h
+++ b/azbox/dmx_lib.h
@@ -8,6 +8,8 @@
 #include <linux/dvb/dmx.h>
 #include "../common/cs_types.h"
 
+#define MAX_DMX_UNITS 4
+
 typedef enum
 {
 	DMX_INVALID = 0,
diff --git a/generic-pc/dmx_lib.h b/generic-pc/dmx_lib.h
index ed38048..754511e 100644
--- a/generic-pc/dmx_lib.h
+++ b/generic-pc/dmx_lib.h
@@ -8,6 +8,8 @@
 #include <linux/dvb/dmx.h>
 #include "../common/cs_types.h"
 
+#define MAX_DMX_UNITS 4
+
 typedef enum
 {
 	DMX_INVALID = 0,
diff --git a/libspark/dmx_lib.h b/libspark/dmx_lib.h
index e85dc3c..af87a02 100644
--- a/libspark/dmx_lib.h
+++ b/libspark/dmx_lib.h
@@ -8,6 +8,8 @@
 #include <linux/dvb/dmx.h>
 #include "../common/cs_types.h"
 
+#define MAX_DMX_UNITS 4
+
 typedef enum
 {
 	DMX_INVALID = 0,
diff --git a/libtriple/dmx_td.h b/libtriple/dmx_td.h
index e657592..a253f3c 100644
--- a/libtriple/dmx_td.h
+++ b/libtriple/dmx_td.h
@@ -14,6 +14,8 @@ extern "C" {
 #endif
 #define DMX_FILTER_SIZE FILTER_LENGTH
 
+#define MAX_DMX_UNITS 4
+
 typedef enum
 {
 	DMX_INVALID = 0,