The 475 Field Communicator is designed to work both as a "Bench Tool" and as a "Field Tool".

• As a Bench Tool, the 475 Field Communicator would typically be connected to one or more FOUNDATION fieldbus devices on the bench with no other host system connected to the segment.
• As a Field Tool, the 475 Field Communicator would be connected to a live FOUNDATION fieldbus segment in the field that is controlled by a Host Control System.

Normally (but not always) this Host Control System acts as the Link Active Scheduler (LAS) for the segment. When the 475 Field Communicator detects that there is a LAS on the segment, it joins the segment as a "guest". For most operations, the Host Control System and the 475 Field Communicator should be able to co-exist on the FOUNDATION fieldbus segment with no problems. Other operations, such as changing the node address of a fieldbus segment, require careful coordination between the Host Control System and the 475 Field Communicator.

Some operations with the 475 Field Communicator are simply not advised if there is a Host Control System on the segment. Some operations (such as changing a device address, changing a device tag, or commissioning / decommissioning a device) with either the 475 Field Communicator or the Host are simply not advised if both a 475 Field Communicator and a Host Control System are on a segment at the same time.