Abstract: Two-way time division multiplex (TDM) links interlace a plurality of digital exchanges such that the possibility of path selection is available for transferring information between two of the exchanges. Instead of conventionally selecting a path for each ordered call set up, the exchanges coact such that there is generally established a one-way TDM loop between all exchanges, this loop being established by parts of said links. For calls between arbitrary exchanges the loop only is used. The operational ability of the links is monitored continuously before and after establishment of the loop. It is possible to reconfigurate the loop during calls in progress for achieving improved information transfer quality.