TM 1-1510-224-10 When    not    in    the    AJ    mode,    it    operates    as    a    tone transmission switch only. c. Standby    Operation.        Normal    operation using     the     aircraft     survivability     equipment/     avionics control system (ASE/ACS) is described in chapter 4. (1) Turn on procedure: 1. AVIONICS MASTER POWER switch (overhead control panel, fig.  2-15) - ON. 2. UHF     transceiver     164 STBY/NORMAL switch   (pedestal   extension,   fig.      2-14)  - STBY. 3. Function    select    switch    -    MAIN    BOTH position, as required. NOTE If function selector is at MAIN setting, only the normal UHF communications  will  be  received.    If selector is at BOTH position, emergency   communications   on   the guard channel and normal UHF communications will both be received. (2) Transceiver operating procedure. 1. Transmitter-intercom selector switch (audio control panel, fig.  3-1) - 3. 2. Microphone switch - Depress to transmit. (3) Preset channel selection. 1. Function selector switch - MAIN. 2. Mode selector switch - PRE. 3. Manual  frequency  selector  switches  -  Set frequency to be placed into memory. 4. Preset    channel    selector    switch    -    Set desired channel number. 5. SET switch - Depress. 3-8. VOICE SECURITY SYSTEM TSECIKY-58 (COMPLETE PROVISIONS ONLY). Complete  provisions  only  are  provided  for  a  TSEC/  KY- 58  voice  security  system.    This  system  provides  secure (ciphered)  two-way  voice  communications  for  the  pilot and  copilot  in  conjunction  with  the  #  1  UHF,  VHF-FM (SINC-GARS),  and  #  2  (BU  VOW)  transceivers.    The system will be  located  in  the  left  equipment  rack  behind  the  pilot. System circuits are protected by the UHF, VHF-FM, and BU VOW circuit breakers on the overhead circuit breaker panel (fig.  2-9). 3-9.      BACK-UP   VOICE   ORDER   WIRE   (BU   VOW) (AN/ARC-1 64). A  transceiver  identical  in  type  and  performance  to  the UHF    transceiver    (fig.        3-3)    is    located    on    the    left equipment  rack,  to  serve  as  a  back-up  voice  order  wire. The transceiver can only be controlled by the ASE/ACS. Standby   control   is   not   available.      The   transceiver   is selected    on    the    audio    control    panel    (fig.        3-1)    by transmitter-intercom   selector   switch   position   number   5 and  by  radio  audio  monitor  control  number  5.    This  set provides  for  secure  communications  through  interfacing with  a  voice  security  system.    The  back-up  voice  order wire   set   is   protected   by   the   7   1/2-ampere   BU   VOW circuit breaker in the overhead circuit breaker panel (fig. 2-8).    The  back-up  voice  order  wire  shares  an  antenna mounted  on  the  aircraft  belly  with  the  transponder  (fig. 2-1 and 2-2). 3-10.        VHF    COMMUNICATIONS    TRANSCEIVERS (VHF-22B). a. Introduction.      The   VHF   communications transceivers (fig. 3-4), provide airborne VHF communications  on  1360  channels  from  118.00  through 151.975    MHz,    and    are    operated    by    two    CTL-22 transceiver     control     units,     located     on     the     pedestal extension (fig.  2-14). The    solid-state    transceiver    includes    capture- effect  automatic  squelch  to  help  prevent  missed  radio calls,    plus    audio    leveling    and    response    shaping    to ensure  audio  quality.    Transmitter  sidetone  comes  from detected  transmitter  signal,  and  is  therefore  a  reliable check  of  transmission  quality.    Each  VHF  transceiver  is powered through its respective circuit breaker, placarded VHF  #  1  or  VHF  #  2,  located  on  the  overhead  circuit breaker panel (fig.  2-9). b. VHF Transceiver Operating Controls (VHF-22B).    All  operating  controls  for  the  transceivers are  located  on  the  CTL-22  transceiver  control  units  and on   the   FM/AM   alternate   communication   switch   panel (pedestal extension, fig.  2-14). (1) Active  frequency  display.    Displays the  active  frequency  (frequency  to  which  the  transceiver is tuned) and diagnostic messages. (2) Transfer/memory switch. This switch   is   a   three-position   spring-loaded   toggle   switch placarded   XFRI   MEM,   which   when   held   to   the   XFR position,  causes  the  preset  frequency  to  be  transferred up   to   the   active   display   and   the   transceiver   to   be returned.    The  previously  active  frequency  will  become the new preset frequency and will 3-7