diff --git a/app/dtmf.c b/app/dtmf.c
index 431b4cc..ca9a1c7 100644
--- a/app/dtmf.c
+++ b/app/dtmf.c
@@ -149,7 +149,7 @@ bool DTMF_CompareMessage(const char *pMsg, const char *pTemplate, uint8_t Size,
 	return true;
 }
 
-bool DTMF_CheckGroupCall(const char *pMsg, uint32_t Size)
+DTMF_CallMode_t DTMF_CheckGroupCall(const char *pMsg, uint32_t Size)
 {
 	uint32_t i;
 
@@ -159,10 +159,10 @@ bool DTMF_CheckGroupCall(const char *pMsg, uint32_t Size)
 		}
 	}
 	if (i != Size) {
-		return true;
+		return DTMF_CALL_MODE_GROUP;
 	}
 
-	return false;
+	return DTMF_CALL_MODE_NOT_GROUP;
 }
 
 void DTMF_Append(char Code)
diff --git a/app/dtmf.h b/app/dtmf.h
index 2227e7b..199fa78 100644
--- a/app/dtmf.h
+++ b/app/dtmf.h
@@ -81,7 +81,7 @@ bool DTMF_GetContact(uint8_t Index, char *pContact);
 bool DTMF_FindContact(const char *pContact, char *pResult);
 char DTMF_GetCharacter(uint8_t Code);
 bool DTMF_CompareMessage(const char *pDTMF, const char *pTemplate, uint8_t Size, bool bFlag);
-bool DTMF_CheckGroupCall(const char *pDTMF, uint32_t Size);
+DTMF_CallMode_t DTMF_CheckGroupCall(const char *pDTMF, uint32_t Size);
 void DTMF_Append(char Code);
 void DTMF_HandleRequest(void);
 void DTMF_Reply(void);