There are 3 Digital Input lines available on the 15 pin socket on the left hand side of the instrument.

The input lines can be used for:
External trig
Start of Logging or
Synchronization of Instruments.

The input signals are 3.3V level (CMOS compatible). An open collector connection will work fine. There is a 10 kohm pull up resistor.
The voltage levels must be within �0.25 V to +3.5 V to avoid harming the instrument.
Pin number 6 holds a constant 3.3V signal (max 10 mA). Pin 14 (and the housing) is digital ground.

Pin number Function
8 DI-1 External trigger
9 DI-2 In Digital input
10 DI-3 In Digital input