One key characteristic of DDLs is the high reliability and low error rate. This is achieved using intelligent alternate routing options in the superordinate network infrastructure and active monitoring via proactive network management. In the event of a malfunction, the system switches to backup lines, either automatically or via operator. Availabilities of well over 99 per cent and error rates below 10exp-6 are therefore typical.
The possible applications for direct data links are diverse and range from connecting branch offices, to interlinking computer centres and providing network connections for telephone systems. Even cloud telephone services can be used via point-to-point internet connections.
A variety of media can be used for establishing direct data links. Dedicated lines were originally based on actual wired connections. DDLs make almost exclusive use of digital multiplex systems which can be set up and managed flexibly by means of a superordinate management system. The customer connection can be made via copper pairs, coaxial cable or fibre-optic cable. The available bandwidths range from a few kilobits to broadband connections of several megabits.