t h e radio transmitter or interphone line for
d. External Switches (Remote). One or more
of the switches described below are required for
use with the control set to permit a user to talk
(2) Crew station switch. A crew station talk
over the interphone line or transmit over radio.
switch, such as Plug, Connector U94A/U (fig.
The quantity and type of switches used will differ
13), is used for connection and control of Head-
between types of aircraft in which they are in-
set-Microphone H101/U. This is a push-to-talk
stalled and may differ between models of the
type of switch normally used by crewmembers
same type of aircraft. Mechanical operation of
who have access to interphone facilities only.
these switches, as well as physical appearance
(3) Hot mike switch. This switch is usually
and panel control markings, will often differ. The
a double-pole, single-throw, locking-type switch.
switches are mounted near a user's station.
It is used to connect the user's microphone output
to the interphone line without holding a non-
(1) Transmit-interphone talk switch.. This
Iocking crew station talk switch or transmit-
switch is usually a double-pole, double-throw,
interphone talk switch in a closed position.
push-to-talk type switch. It is used to select either