TM 1-1510-218-10 3-6 (a)  Identifier. (b)  Latitude and Longitude. (c)  Additional   data   depending   on   how user defines waypoint: 1   User airports (elevation and surface of longest runway). 2   User VOR (frequency and magnetic variation). 3   User NDB (frequency). Waypoints are stored in the KLN 90B database almost exclusively by their ICAO identifiers. NOTE There are several exceptions in Alaska.  In many    cases,    airports    with    three    letter identifiers receive the prefix "P", but there are   many   that   don't.      The   most   reliable method   of   determining   an   Alaska   airport identifier  is  to  look  it  up  from  the  airport name or city. Not  all  airports  receive  the  prefix  letter.    Airport identifiers     that     are     combinations     of     letters     and numbers do not receive the prefix letter. (8)   Database Update.  There are two ways to update the database. (a)  Cartridge Exchange. The new update may be installed any time prior to the effective date and the KLN 90B will use the previous data up to the  effective  date  and  automatically  begin  using  the new data on the effective date. 1.  Insert     the     KLN     90B     insertion/ removal    tool    in    the    small    hole located on the right side of the unit.   A  standard  3/32-inch Allen wrench may also be used. 2.  Turn tool counterclockwise until the locking mechanism becomes loose and then continue turning counter- clockwise until it just barely begins to  become  snug.    Do  not  turn  so far counterclockwise that the mechanism  starts  to  bind  and  can no longer be turned. 3.  Pull   the   unit   out   of   the   rack   by pulling  on  the  sides  of  the  panel.   DO NOT PULL ON THE KNOBS. 4.  Remove the old cartridge by pulling it straight out of the back. 5.  Insert  new  cartridge  into  the  back of the KLN 90B as indicated by the label  on  the  cartridge.    When  the cartridge  is  properly  inserted,  the "Insert   To   Here"   marking   on   the label  can  just  be  seen  protruding from the rear of the unit. 6.  Make   sure   the   front   lug   of   the locking   mechanism   is   in   the   UP position   and   insert   unit   into   the rack as far as it can go. 7.  Re-insert  tool  and  turn  clockwise until   snug.      Pull   gently   on   front panel to   verify  unit  is  locked  into the rack. (b)  Laptop computer using 3.5-inch diskettes. 1.  Plug 9-pin female connector end of interface  cable  into  a  COM  serial port of computer. 2.  Plug the other end of the interface cable  into  the  data  loader  jack  on the annunciator panel. 3.   Turn   on   computer,   insert   Disk   1 and  the  program  will  automatically load  and  the  screen  will  indicate ready. 4.   Turn  on  the  KLN  90B.    Press  ENT as   required   to   approve   the   Self- Test   and   Database   pages.      Use the  left  outer  knob  to  select  the Setup  (SET)  type  pages  and  the left inner knob to select the SET 0 page. NOTE In  steps  5,  6,  and  7  repeated  presses  of CLR  terminate  the  process  and  bring  the display back to the original SET 0 page. 5.   Press the left CRSR button.    UPDATE PUBLISHED DB  will now be displayed.