In TEM systems, there are different types of shutters for STEM detectors and CCD cameras, including gun-tilt shutter (normally called shutter 1 in JEOL TEM system), electrostatic shutter (normally called shutter 2 in JEOL TEM system), and mechanical shutter.

Different shutter has different cable to connect the hardwares, for instance, "PL shutter" cable on Gatan box connects mechanical shutter and "electrostatic shutter" cable on Gatan box connects electrostatic shutter.

Note that on DigitalMicrograph software, mechanical shutter is sometimes called “post specimen” shutter, gun tilt shutter is sometimes called "pre-specimen" shutter, and electrostatic shutter is called "post-specimen" shutter even though it is really a pre-specimen shutter. In order to have a shutter working, the relevant button on software (e.g. DM) should be on. It is important to note that that turning a shutter on causes a small amount of electrical interference even thought it might be negligible.

Note that a good method to do low-dose STEM imaging is to use a proper fast shutter (e.g. ultrafast electrostatic shutter) to move the beam on/off the specimen to control the dose and to avoid any change in the electron optics.