2 Features and Functions28 Keysight U2781A User’s GuideExternal Trigger OutTrigger Out selects one of the eight lines from trigger bus (TRIG [0..7]) as anexternal trigger source. The selection of the trigger out line is done by the USBdevice in the chassis as illustrated in Figure 2-2 by means of a multiplexer.Table 2-2 defines the available trigger out signals provided by U2300A, U2500A,and U2600A Series DAQ, whereas for U2700A Series modular products, user isallowed to choose any trigger line from the trigger bus (TRIG [0..7]) as an externaltrigger source.The SCPI command below is used to select one of the lines or bits of the triggerbus (TRIG [0..7]) as an external trigger source:TRIGger:OUT {0|1|2|3|4|5|6|7}Table 2-2 Trigger out bits for U2300A, U2500A, and U2600A Series DAQ devicesTrigger Out FunctionBit-0 Time baseBit-1 ReservedBit-2 ReservedBit-3 A/D triggerBit-4 ReservedBit-5 ReservedBit-6 ReservedBit-7 D/A trigger