diff --git a/app/src/main/java/com/huawei/ims/HwImsCallSession.kt b/app/src/main/java/com/huawei/ims/HwImsCallSession.kt
index d17fef9..9a7f013 100644
--- a/app/src/main/java/com/huawei/ims/HwImsCallSession.kt
+++ b/app/src/main/java/com/huawei/ims/HwImsCallSession.kt
@@ -142,7 +142,7 @@ class HwImsCallSession
             }
         }
 
-        mProfile.setCallExtra(EXTRA_OI, (if (call.isMT == 0) "" else "+") + call.number)
+        mProfile.setCallExtra(EXTRA_OI, (if (call.isMT > 0) "+" else "") + call.number)
         mProfile.setCallExtraInt(EXTRA_OIR, hwOirToOir(call.numberPresentation))
         mProfile.setCallExtra(EXTRA_CNA, if (call.name.isEmpty()) call.number else call.name)
         mProfile.setCallExtraInt(EXTRA_CNAP, hwOirToOir(call.namePresentation))