In some installations where a panel mounted IFD5XX/4XX is interfaced with a remote transponder such as an AXP322 the IFD100 IPAD application has been reported to populate a "No Comm With XPDR" CAS message alert. 

If the message is only present on the IFD100 but not on the Panel Mount IFD5XX/4XX, this is because the IFD100 is attempting to control the remote transponder and the panel IFD5XX/4XX is not allowing it. The IFD100 will flag this alert as a nuisance because the panel is purposely keeping it out of the control line.

If the message shows on both the panel and the IPAD IFD, there is an issue and the interface between the IFD5XX/4XX and the remote transponder must be diagnosed. 

At this time there is no action to remove the nuisance message from the IFD100, the Transponder Thumbnail Datablock will still show correct information, on the IFD100.