Realtime VLBI system using public ATM network

VLBI is an important application of ATM technology because it can transmit huge amounts of data. A single VLBI experiment typically generates data (wh ich must be recorded and transported until they are cross-correlated) of te rabit order at each separated observing site. Conventional VLBI not only re quires manpower but also limits the maximum observation data rate. Therefor e, a realtime VLBI using a private ATM network was developed recently, but it could not be utilized for regular VLBI experiment. Since utilization of public ATM is most realistic solution for realtime VLBI between ordinary ob serving sites, we have developed an interface equipment that connects VLBI observation and processing equipment to a public ATM network and demonstrat ed a successful experiment. This equipment supports VLBI's standard bit rat es as 128 Mbps and 256 Mbps, though data rate for user's payload in 155.52 Mbps (STM-1/OC-3) ATM network is actually only 119.5 Mbps. It can easily st ep to higher networks as 622 Mbps.