(see Figure 64)

Independent private networks which start with an internal clock master (an OpenScape 4000 system is designated as the network clock master) or private networks with their own standard clock (the OpenScape 4000 system with an external clocking source from a standard clock is designated master) are plesiochronous or pseudosynchronous with an exactness of 1 x 10 to the power of minus 11 with regard to other networks to which they are digitally connected.

( --> Special cases, SDH)

The system designated as clock master in the network or which is provided by the standard clock is referred to as level = 0. Then the same procedure used for synchronous networks is applied for the clock hierarchy levels. If the network comprises more than four systems, the master system should have a networking clock generator. This also applies to private networks synchronizing onto the public network using an SASE but change to an autonomous clocking state in the case of trunk errors (the SASE changes to hold over or free-run mode or synchronizes onto a backup clock normal).

( --> Selection of clock generators)