As above - it is not common in the sense that all systems work in that way or in the same way. Older systems are less likely to offer the facility or a suitable interface, more modern systems are no doubt designed to incorporate the facility although I suspect that some may use a proprietary interface.
As with any data system, it is possible for data to be wrong - GIGO. I suspect that radar display systems will use whatever they are fed with - within the usual sensible bounds - on the assumption that the data is validated downstram of the originating interface. So if a radar display is fed with a pressure value that is between, say, 950 and 1050 hPa (the usual bounds used), it will not know if the value is right or wrong. I have seen a system which deemed the 'current' value expired after 40 mins or thereabouts and to flag this to the controller but I can't recall which company made it. I don't think radar displays usually continually 'handshake' with whatever system is supplying the pressure data so a failure of the comms feed or data source would not be likely to be detected.
Last edited by Spitoon; 26th Aug 2008 at 19:37.