TM 1-1510-224-10 inverters  are  controlled  by  two  three-position  switches placarded 3f  AC CONTROL, # 1 and # 2 INV, RESET - ON - OFF, located on the mission control panel (fig. 4- 1). Section II.  COMMUNICATIONS 3-4. COMMUNICATIONS EQUIPMENT GROUP DESCRIPTION. The   communications   equipment   group   consists   of an intercom system connected to individual audio control panels for the pilot and copilot which interface with VHF, UHF,   BU   VOW,   VHF-FM,   and   HF   transceivers,   and provide  reception  of  audio  from  VOR,  localizer,  marker beacon, TACAN/DME, and ADF receivers. 3-5. MICROPHONES, SWITCHES, AND JACKS. Boom    and    oxygen    mask    microphones    can    be utilized in the aircraft. a. Control  Wheel  Microphone  Switches.    The  pilot and  copilot  are  each  provided  with  bi-level  microphone switches placarded  MIC,  INTPH  -  XMIT,  located  behind the  outboard  handgrip  of  their  respective  control  wheels (fig.        2-24).        When    the    control    wheel    microphone switches    are    depressed    to    the    first    level    (INTPH position),    voice    audio    signals    from    the    respective microphone   are   routed   to   the   intercom   system   (the position   of   the   transmitter-intercom   selector   switch   is disregarded). When   the   control   wheel   microphone   switches   are depressed   to   the   second   level  (XMIT   position),   voice audio signals from the respective microphone are routed to   the   transmitter   selected   by   the   transmitter-intercom selector  switch  (located  on  the  respective  audio  control panel, fig. 3-1). b.Cockpit   Floor   Foot-Operated   Microphone   Switches. The   pilot   and   copilot   are   each   provided   with   a   foot- operated microphone switch, placarded  MIC,  located  on the    cockpit    floor,    forward    of    their    respective    seat positions. Depressing  the  foot-operated  microphone  switches routes   audio   signals   to   the   device   selected   by   the transmitter-intercom    selector    switch    located    on    the respective audio control panel (fig.  3-1). c. Microphone    Jack    Selector    Switches.          Two switches, placarded   MIC,  HEADSET  OXYGEN  MASK, located on the left and right sides of the instrument panel (fig.        2-18),    provide    a    means    of    selecting    which microphone   jack   is   connected   to   the   audio   system. When    the    pilot's    or    copilot's    switch    is    set    to    the HEADSET position, the headset jack is connected to the respective   audio   system.      When   set   to   the   OXYGEN MASK position, the   oxygen   mask   jack   is   connected   to   the   respective audio system. 3-6. AUDIO CONTROL PANELS. a. Description.      Separate   identical   audio   control panels (fig.  3-1), located on the left and right subpanels (fig.    2-8),  are  provided  for  the  pilot  and  copilot.    Each audio   control   panel   is   powered   by   its   respective   2- ampere    circuit    breaker    placarded    AUDIO   PILOT    or AUDIO COPIL,  located  on  the  overhead  circuit  breaker panel (fig.  2-9). b.VHF-FM/VHF-Alternate  Communication  Switch  Panel. An   alternate   communication   switch   panel   with   three alternate-action (push on, push off) switches, located on the pedestal extension (fig.  3-2), allows position 2 of the audio   control   panel   transmitter-selector   switch   to   be connected to an alternate transceiver. (1) VHF-FM/VHF-AM alternate communication  selector  switch.    The   center   alternate- action    (push    on,    push    off)    alternate    communication switch   is   placarded   FM,   AM.      When   the   switch   is depressed, either  FM or   AM  will  be  illuminated.    When the switch is set to the FM position, position number 2 of the  transmitter  selector  switch  (audio  control  panel,  fig. 3-1)    and    number    2    radio    monitor    control    will    be connected  to  the  VHF-FM  (SINCGARS)  transceiver  for both transmit and receive functions.  When the switch is set    to    the    AM    position,    position    number    2    of    the transmitter selector switch (audio control panel, fig.  3-1) and the number 2 radio monitor control will be connected to  the  VHF-AM  number  2  transceiver  for  both  transmit and receive functions. (2) Pilot's and copilot's alternate communication monitor switch. The pilot and copilot are each provided with an alternate action (push on, pull off) alternate  communication  monitor  switch,  located  on  the left  side  (pilot's  switch)  or  right  side  (copilot's  switch),  of the    alternate    communication    switch    panel    (pedestal extension,   fig.   2-14).      Both   switches   have   illuminated placarding  which  reads   MON,  ON  -  OFF.      When   the switch    is    depressed,    either ON    or     OFF    will     be illuminated.    When  either  of  the  switches  is  set  to    ON and the center switch is set to  FM, the VHF-AM number 2  audio  will  be  heard  in  addition  to  the  FM  audio.    The FM audio cannot be monitored when the center switch is set to   AM.      The   monitored   audio   volume   will   not   be controlled by the number two radio monitor control. 3-2