The toggle switch near the joystick provides for a rapid means of moving the stage up & down. Fine control of z position is accomplished with the Z focus knob, or by computer control.
There is an option to control the Z focus with foot switches as well. If this option is requested the 9 pin serial out connector is used to connect the foot switches, and is labeled as such.
Please refer to ZF LOCK (FTP firmware) module Operation page for more info on FTP controller firmware.