The Message Path for a DF1 message consists of the Port Number and the Destination Address.
On most Logix controllers, the serial port is Port 2.
A message addressed from a Logix controller to a DF1 device at Node 7 would use the path "2, 7".
CompactLogix controllers that have two serial ports (1769-L30, -L31) number them as Channel 0 = Port 2, Channel 1 = Port 3.