Since the demise of the ECN and RTTY emergency networks between local authorities, most emergency traffic has been carried on VHF and UHF voice links, mainly on FM. Whilst we are all delighted not to have to hump Creed 444s around anymore, there is still a need to be able to transfer data reliably during emergencies. Many Raynet groups have used packet to meet this need. Practical trials however have always shown that net operations using this mode are problematic unless unconnected modes are used. Moreover, trials of rest centre manning revealed problems in producing hard copy messages for the user services under high traffic densities.
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