You may have noticed that in some Tadano Lift scenarios, there are two hoist levers, instead of a telescoping lever and hoist lever. In these scenarios, the telescope function is toggled off and an auxiliary hoist function is toggled on, which allows you to hoist lighter loads with the headache ball. In other Lift scenarios, the crane is equipped with the headache ball and the main load block. In these scenarios, the main hoist is controlled with the hoist lever on the right side for hoisting heavier loads.
In any scenario where Auxiliary hoist is enabled, you can toggle between this function and telescope by pressing this green button, using the gaze cursor and horn button:
Keep in mind that while telescoping, both your main and aux hoist cables will need to be adjusted as the boom scopes in or out, and pulls in or lets out cable, respectively.