Cause:

• The host adapter identifies C/CON and EPC/CON concentrators by their node numbers. Each concentrator in a daisy chain must have a unique node number, which must be set during installation. The node numbers must be assigned in ascending order with the lowest number assigned to the concentrator closest to the host adapter. It is permissible to skip node numbers (to facilitate insertion of addi-tional concentrators at a later date), as long as the ascending sequence is maintained. The node number of the first concentrator in the chain must be set to "1n" when it is first installed.

Solutions:

• Turn the concentrator on and wait for the POST (Power On Self Test) to complete. When “P1” is displayed on the front panel 7-segment LED display, press the right-hand button once. The current node number will be displayed (“1n”, for Node 1, if the concentrator has just been unpacked). Press the left-hand button to advance the node number through the eight possible settings (1n-8n). Once “8n” has been reached, the numbers start over at “1n”. When the desired node number is displayed, press the right-hand button again to select the number. The display should now read “Pn” (indicating a “pass” condition). If there was an error, the display will read “Fn”. If you are adding concentrators to an existing system which has older concentrators (these have a metal case), the node numbers of the new concentrators must begin with a number that is greater than the total number of older concentrators connected to that EIA-422 synchronous line. In the case of duplicate node numbers, the concentrator farther from the host adapter will display “En”, instead of “AC” when the system is booted up.