Siemens SINUMERIK 828D Operating Manual page 657

Program view in the G code
1) Machining program in the leading channel
2) Machining program in the following channel
3) 2-channel stock removal cycles, which contain implicit WAIT marks, are identified by a preceding clock symbol.
Figure 10-4 View of a 2-channel stock removal program in G code
Turning
Operating Manual, 01/2015, 6FC5398-8CP40-5BA2
Multi-channel machining
10.2 Multi-channel support
657