Each system must have one of these modules as they provide the routing for the timing signals and the connectors for external control and synchronization. They also contain the power switch rod and supply health indicator.
D334B Sync
This basic module is not shown but is the same as the left-hand side of the D341.
D331AT Sync & Gate
This double-width module adds the control of Gating the duration of a burst of pulses to the basic functions.
D341A Sync & Train
This module is similar to the D331AT but controls the Gating as number of pulses in a burst.