The Sync module is plugged directly into the slot of the CPU 41xH reserved for it. Two Sync modules are required for each CPU. Modules in the subunits are connected by means of fiber-optic connecting cables.

• Sync module 6ES7960-1AA06-0XA0 for fiber-optic cables up to 10 m in length (patch cable).
• Sync module 6ES7960-1AB06-0XA0 for fiber-optic cables up to 10 km in length (patch cable or installation cable).