I have a new Minoston Z-Wave Mini Plug.  I works in the same room as the ISY, but if I move it to another room, I can not communicate with it.  I have multiple Insteon devices in remote areas of the house that work.  What is the  issue with the Z-Wave device?

Z-Wave device range is typically fairly small inside a building/home due to many factors.  Z-Wave overcomes this by using a mesh network design where the messages can be repeated by their neighboring nodes until the message gets to the correct destination.  For a Z-Wave network to work properly and efficiently it takes multiple nodes to form the mesh.  Most if not all Z-Wave Plus Powered devices (plugin modules or hard wired) are all repeaters and help form the mesh.  Battery operated devices do not repeat messages and do not help with building a mesh.

Insteon uses it's own distributed network topology where every powered node will rebroadcast messages and the destination will then respond.  Insteon also uses the powerline as a network connection as well as RF for dual band devices.  In a clean power environment Insteon is absolutely great.  

1 hour ago, DHughes said:

I have a new Minoston Z-Wave Mini Plug.  I works in the same room as the ISY, but if I move it to another room, I can not communicate with it.  I have multiple Insteon devices in remote areas of the house that work.  What is the  issue with the Z-Wave device?

You need a Z-Wave repeater such as the Aeotec Range extender 7:   Z-Wave repeater and range extender • Aeotec Range Extender 7 (ZW189)

The extender should be placed no further than about 15 feet from the ISY. The range will be increased if you're using the ISY 500 series dongle rather than the 300 series.