diff --git a/sonoff/sonoff.h b/sonoff/sonoff.h
index 0869c6929..22be17380 100644
--- a/sonoff/sonoff.h
+++ b/sonoff/sonoff.h
@@ -48,6 +48,8 @@ typedef unsigned long power_t;              // Power (Relay) type
 #define MAX_FRIENDLYNAMES      4            // Max number of Friendly names
 #define MAX_DOMOTICZ_IDX       4            // Max number of Domoticz device, key and switch indices
 #define MAX_DOMOTICZ_SNS_IDX   12           // Max number of Domoticz sensors indices
+#define MAX_KNX_GA             10           // Max number of KNX Group Addresses to read that can be set
+#define MAX_KNX_CB             10           // Max number of KNX Group Addresses to write that can be set
 
 #define MODULE                 SONOFF_BASIC // [Module] Select default model
 
@@ -173,4 +175,4 @@ const uint8_t kDefaultRfCode[9] PROGMEM = { 0x21, 0x16, 0x01, 0x0E, 0x03, 0x48,
 
 extern uint8_t light_device;  // Light device number
 
-#endif  // _SONOFF_H_
\ No newline at end of file
+#endif  // _SONOFF_H_