TM 1-1510-225-10 3B-146 3.   The  NDB  frequency  associated  with the    approach,    if    any.        The    NDB frequency     is     the     frequency     of     a compass  locator  at  the  outer,  middle, or inner marker beacons. (3)   Vertical  Scrolling.    Vertical  scrolling  has the following characteristics: 1.   Will access additional approach frequency data for other runways and wrap around in both directions if more than one page of information exists. 2.   Data   line   1   will   remain   fixed   during scrolling. The  frequencies  will  be  displayed  in  groups  of three  per  page.    A  maximum  of  12  frequencies  or  4 pages may be accessed. t.    Communication Radio Control. (1)   Communication  Radio  Control  Overview.   The     FMS-800     provides     control     of     the     following functions from the CDU, for the ARC-210 V/UHF radio: 1.   V/UHF radio mode selection. 2.   V/UHF radio squelch, bandwidth, tone, and modulation control. 3.   V/UHF radio scanning  operation. 4.   HAVE    QUICK    I/II    function    control, including MWOD and FMT list selection,   time   synchronization,   date entry, MWOD verification, and SINCGARS control functions. In addition, the Flight Displays provide heads up control and display of the communication radios. Communication     radio     frequency     selection     is available via the communication page by selecting the COM  function  key  of  the  CDU.    The  V/UHF  control pages     provide     the     basic     radio     control     features.   Specialized pages such as the V/UHF HAVE QUICK II setup  pages  and  SINCGARS  control  pages  are  also available. If  the  FMS-800  cannot  interface  with  a  radio  for any reason (i.e., LRU failure, data bus failure, etc.), a check mark ()  will  be  displayed  to  the  left  of  the  title line of all pages corresponding  to that radio.  A   will also    be    displayed    on    the    communication    pages adjacent to the preset number of the LRU. Power  to  the  communication  radio  is  controlled via the power pages. The     FMS-800     also     has     provisions     for     an external,  crew  activated  emergency  mode  switch  for setting all communication radios to emergency frequencies, if installed on the aircraft. (2)   V/UHF Radio Control. (a)   V/UHF   Frequency   Selection.      The crew    may    tune    the    V/UHF    radios    by    frequency, callsign, maritime channel, or preset number.   Frequency     tuning     is     performed     directly     on     the Communications page by entering the desired frequency in the scratchpad and pressing the channel selection line select key.  Refer to Figure 3B -118 and Table  3B -81.    A  valid  frequency  is  entered  as  two  to three digits  followed  by  up  to  four  decimals,  followed by A, AM, F, or FM to define the modulation type.  An M  is  displayed  as  the  preset  number  to  indicate  the frequency  was  entered  manually.    Possible  ways  of tuning    the    communication    radio    are    with    manual frequency     selections (including frequencies, net identifiers, or maritime channel entries), preset callsign entry,  preset  number  selection,  or  airport  frequency selection. Figure 3B-118.  Frequency Control, Communication Page Table 3B-81.  Frequency Control, Communication Page NO. DESCRIPTION/FUNCTION 1 Pressing    the    function    key    COM    will access the communication page. 2 Enter   airport   identifier   and   access   the V/UHF airport frequency page.