According to the invention, a reduced set of transport format combinations
is signalled to a subscriber station which has established a link to a second radio
communication system in a second signalling channel of said second radio communication
system. The transport format indicator is then selected from the reduced set of
transport format combinations and used to initiate a link transfer to the first
signalling channel of a first radio communication system. A full set of transport
format combinations is subsequently signalled to the subscriber station in the
first signalling channel.