TM 1-1510-225-10 3A-46 Momentarily pressing the frequency transfer switch will change  the  receiver  control  unit  back  to   the  standby entry   mode   and   will   return   the   standby   frequency display to the frequency displayed before entering the active frequency mode. (3)   Channel   Mode.      Pressing   the   channel switch, placarded   CHAN,  will  put  the  receiver  control unit   into   the   channel   mode.      When   in   the   channel mode,  the  channel  number  is  displayed  in  the  active frequency    display    and    the    channel    frequency    is displayed  in  the  standby  frequency  display.    Channel frequencies  must  be  set  with  the  unit  in  the  program mode. (a)   When  the  receiver  control  unit  is  in the  channel  mode,  the  receiver  will  be  tuned  to  the frequency  that  is  displayed  in  the  standby  frequency display.    If  no  channels  have  been  programmed,  the receiver control unit will display channel 1 (CH 1) with dashes in the standby frequency display for 5 seconds,  then  the  unit  will  tune  the  receiver  to  the last    frequency    displayed    in    the    active    frequency display. (b)   Pressing     the     transfer     switch     for 2 seconds will change the receiver control unit to the active frequency entry mode. (4)   Program   Mode.      The   frequencies   and channel  numbers  used  in  the  channel  mode  must  be programmed into memory with the receiver control unit in the program mode. (a)   Pressing the  CHAN  switch for longer than  2 seconds  will  put  the  receiver  control  unit  into the program mode.  The channel number that was last used will be displayed flashing in the active frequency display.    With  the  channel  number  flashing,  rotating the tuning knobs will change the channel number.  A channel  number  with  no  programmed  frequency  will have dashes in the standby frequency display.  In this case   the   receiver   will   be   tuned   to   the   last   valid frequency  displayed  in  the  active  frequency  display.   Taking  the  receiver  control  unit  out  of  the  program mode with dashes in the standby frequency display will deprogram   that   channel.      Pressing   the   frequency transfer switch will cause the channel number to stop flashing  and  the  frequency  to  start  flashing.    Change the  frequency  by  rotating  the  tuning  knobs.    Pressing the   frequency   transfer   switch   again   will   cause   the frequency  to  stop  flashing  and  the  channel  to  start flashing. (b)   The receiver control unit will return to the   standby   frequency   entry   mode   by   pressing   the CHAN switch or a period of no activity for 20 seconds.   The frequency mode prior to channel or program mode will    be    resumed,    with    the    receiver    tuned    to    the frequency in the active frequency display. d.  Normal Operation. 1.   Power  and  mode  switch   –  ANT,  ADF,  or TONE (BFO). 2.   Tuning knobs – Set desired frequency. 3.   ANT function  – Position power and mode switch   to   ANT.      Select   ADF   on   audio system and adjust volume. 4.   ADF function  – Position power and mode switch    to    ADF.        Bearing    pointer    will indicate relative bearing to tuned station. 5.   TONE    function    –    Position    power    and mode  switch  to  TONE  (BFO).    A  1000-Hz tone will identify keyed CW stations. (1)   Self-Test. 1.   Power and Mode Switch – ADF. 2.   Tuning Knobs  –  Tune  a  nearby  NDB, compass locator, or broadcast station. 3.   Power,    Volume,    and    Mode    Control Knob  –  Press  to  begin  test.    Bearing pointer will rotate 90 from the previous  valid  indication.  Press again and    verify    that    the    bearing    pointer returns to previous valid indication. NOTE If  the  signal  received  is  weak  or  of  poor quality,   bearing   pointer   rotation   will   be slow. 3A-27.  RADIO MAGNETIC INDICATORS (KNI 582). a.   Description.    The  pilot  and copilot are each provided  with  an  identical  Radio  Magnetic  Indicator (RMI),  which  provides  aircraft  magnetic  heading  and radio bearing information to a selected VOR, TACAN, NDB,   or   FMS   waypoint.      The   RMI's   are   powered through two 1-ampere circuit breakers, placarded, RMI NO. 1 and  NO. 2, located on the right sidewall circuit breaker panel, Figure 2-6. b.  RMI   Controls   and   Functions   (KNI   582).   Refer to Figure 3A-22. (1)   Heading Flag.   The heading flag comes in to  view  when  heading  information  displayed  on  the compass card is invalid.