diff --git a/utils/fgcom/fgcom_external.cxx b/utils/fgcom/fgcom_external.cxx
index 44f6bc9..5a01196 100644
--- a/utils/fgcom/fgcom_external.cxx
+++ b/utils/fgcom/fgcom_external.cxx
@@ -483,6 +483,13 @@ std::string computePhoneNumber(double freq, std::string icao, bool atis)
              (int) (freq * 1000 + 0.5) );
     exten[16] = '\0';
 
+    sprintf( exten,
+             "%02d%06d",
+             prefix,
+             (int) (freq * 1000 + 0.5) );
+    exten[8] = '\0';
+
+
     snprintf( phoneNumber,
               sizeof(phoneNumber),
               "%s:%s@%s/%s",