PSS®E is secured through the use of hardware locks, or "dongles". Each machine on which PSS®E is installed will require a pass-through hardware lock to be installed on its parallel port. (Optionally, a USB-based "dongle" can be provided for use under Windows XP or VISTA). Alternatively, if your network supports the TCP/IP protocol, PSS®E can be installed to use a single network lock on a Windows XP or Server 2003 system. For further details on network locking, please contact Siemens PTI.