Place call  to  DISA facility of the system. 2.  At receipt of Intercom dial tone/AA  announcement, dial as  desired.   If  DND Warning tone is received, enter an Authorization Code, to receive Intercom dial tone. Conditions 1.  Each CO/IP path is separately assigned for DISA operation during Day, Night and/or Timed system operation mode.  DISA operation is active  only when the system  is in the  assigned operating mode(s). 2.  DISA callers can be routed to a  VMIM/VSF  Auto Attendant announcement in place of Intercom dial tone.  The  announcement can be associated with a CCR  Table or assigned to disconnect  after playback (‘#’). 3.  A DISA caller can be required to enter an Authorization Code  to access  the system’s  external outgoing resources, facilities or features.  If required, the caller is permitted to retry entry of a valid Authorization Code based on  the DISA  Retry count.  Continued failure results in disconnect. 4.  DISA callers are subject  to COS dialing restrictions.  If Authorization Codes are required and the code entered matches a Station Authorization Code, the station’s COS  will apply.   Otherwise, the assigned DISA COS will apply.  In both cases, the  CO/IP  COS for the outgoing path will be active. 5.  The system will disconnect an outgoing DISA call if the  Unsupervised Conference timer expires or disconnect supervision is received.   A disconnect warning tone is provided 15 seconds prior to disconnect. 6.  If a DISA caller encounters a system All Lines Busy, busy tone is received for 5 seconds before ICM  Dial tone is  again presented and the  DISA caller may try another call. 7.  LEDs associated with the DISA CO  Line appearance will provide normal status indications at all stations  except the Attendants.   The LED for the line at  an Attendant will flutter  at 240 ipm when busy. 8.  An iPECS  Phone user can only receive a DISA call with an available CO/IP appearance button.