TM 55-1510-219-10 keys in sequence, starting with "E". (Example: 20.1" East = E 201.) 12. INSERT/ADVANCE push-button - Press. (Observe pushbutton light extinguishes.) NOTE In above example, if INSERT/ADVANCE pushbutton were pressed, the following normal     display     would     appear: "42°54.5 N" and "87°54.3 W".  The extra  precision  values  are  added to    normal    values    and    normal displays are not rounded off. NOTE The normal geographic coordinates must always be loaded   prior   to   extra   precision values. NOTE The directions "N" or "S" and "E" or    "W"    are    established    during normal   coordinate   entry.      Either key  may  be  used  to  initiate  entry during  extra  precision  loads  and the  values  will  be  added  to  extra precision  value  without  affecting direction. NOTE It is characteristic of the computer display   routine   to   add   0.2   arc- seconds   to   any   display   of   59.9 arc-seconds. The value in computer is as loaded by operator. 13. INSERT/ADVANCE    push-button    - Press. (Observe    that    right    data    display    indicates    last previously   inserted   altitude,   and   left   data   display   is blank.) 14. To   indicate   the   following   load   is altitude - Press key "4" or "6". (Observe INSERT/ADVANCE pushbutton light illuminates.) 15. To   load   altitude   -   Press   keys   in sequence. (Example: 1230 ft = 1230.  Numbers appear in right data display as keys are pressed. NOTE Altitude inputs are limited to 15,000 feet. 16. INSER/ADVANCE push-button - Press. (Observe pushbutton light extinguishes. 17. INSERT/ADVANCE    push-button    - Press. (Observe     that     left     data     display     indicates     last previously   inserted   channel   number,   and   right   data display is blank.) 18. To   indicate   the   following   load   is channel  number  -Press  key  "2"  or "8". (Observe INSERT/ADVANCE pushbutton light illuminates) 19. To   load   channel   number   -   Press keys in sequence. (Example:  109  =  109.    Numbers  appear  in  left  data display as keys are pressed.) 20. INSERT/ADVANCE    push-button    - Press. (Observe pushbutton light extinguishes.) NOTE Any  number  will  be  accepted  by the   INS;   however   only   stations with    a    channel    number    within range   of   1   through   126   will   be used for TACAN mixing. NOTE The channel number has an implied "X" suffix. NOTE Decimal points and degree symbols   should   be   disregarded when reading altitude and channel number displays. 21. INSERT/ADVANCE  push-button - Press. (Observe station latitude and longitude reappear.) 22. Repeat steps 3 through 19 for each TACAN station. 23. To   return   INS   to   normal   display modes, momentarily set data selector to L/L POS. 3-57