PS Engineering
PMA7000M-S Series Audio Selector Panel and Intercom System
Civil Air Patrol Version Installation and Operator’s Manual
200-072-0004
Page 2-7
Rev. 4, Sept. 2000
2.5.12 PA Mute (J1, Pin 18)
Pin 18 of J1 is TTL logic output that is pulled low during PTT operation. This serves as
an input to external public address system to prevent feedback during transmissions.
2.5.13 P-T-T Intercom (J2, Pin 18, L and M)
To provide intercom in high noise environments, Pins L, 18 and M of the top connector
can be used. Connect pin 18 to ground through a SPST switch to inhibit
IntelliVox
™.
Connecting Pin M through a momentary switch to airframe ground will activate the pi-
lot’s microphone for intercom, grounding pin L will activate the copilot’s microphone.
For passengers to have PTT intercom, connect a momentary N.O. switch in series with
mic audio.
2.6 Marker Installation (PMA7000M-S)
The marker beacon receiver is an option included in the PMA7000M-S.
NOTE:
Non-marker units can NOT provide audio interface with an external marker receiver
through an auxiliary input.
2.6.1 Middle Marker Sense (PMA7000M-S)
A Middle Marker sense output signal is available from the 7000M and 7000M-S to flight
control systems. This function will not operate during the test mode. This output will go
to +4.75 VDC (
±
0.25 VDC) when a valid Middle Marker signal is received. This output
is J1, pin 2.
2.6.2 External Marker Lights (PMA7000M-S)
For installations that require external marker beacon lights, there are three outputs that
can drive 12-Volt lamps only. The external output lamps are driven high (+9 VDC
±
1.5
VDC) when active. Maximum source current per lamp is 125 mA. Voltage varies with
photocell dimming.
2.6.3 Marker Antenna Installation
Refer to aircraft and antenna manufacturer's installation instructions, as well as AC43.13-
2A (or later revision), Chapter 3, for information on proper antenna installation tech-
niques. The marker beacon antenna must be mounted on the bottom of the aircraft.
2.7 Adjustments
The PMA7000M-S is factory adjusted to accommodate the typical requirements for most
aircraft configurations. There are five adjustments however, that will allow the installer to
tailor the specific functions.
