The stepper controller has a universal modem friendly user programmable interface. To use it, you need a Phone line simulator and an external Hayes-compatible modem, hooked to one of controler serial port (Input). If necessary, standard adapters DB9-DB9, DB9-DB25 can be used. When power is switched on, the controller detects the modem and runs a sequence of user preprogrammed instructions, which initiate the modem. The modem initiates communication with a remote computer and gives control to it. Set of simple commands preprograms modem interface instructions, tests and traces them. The instructions are saved into nonvolatile flash memory and become default. This will cause the controller to automatically use the saved instructions if modem is detected after the controller reset or reboot (controller also reboots if modem communication is disconnected). If the modem is not detected, the controller initiates standard RS232 communication.