PS Engineering
PMA450B Audio Selector Panel and Intercom System
Installation and Operator’s Manual
200-450-0600
Page 2-7
Rev. 5, August 2020
2.4.13.1 Cell phone Sidetone
The PMA450B provides cellular telephone sidetone (the user’s voice fed back to the headset). Some cell
phones provide sidetone, and may have poor audio quality if both sources are combined. The cell phone
sidetone is adjustable in the Bluetooth® operation screen
Marker Beacon Installation (050-450-0601, -0602 Only)
2.5.1
Marker Antenna Installation
A marker beacon antenna, appropriate to the type and speed of the aircraft, is required (not included). Refer
to aircraft and antenna manufacturer's installation instructions, as well as AC43.13-2B (or later revision),
Chapter 3, for information on proper antenna installation techniques. The marker beacon antenna must be
mounted on the bottom of the aircraft.
2.5.2
External Marker Lights
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 (typ7.0 VDC
4.0 VDC unloaded, at MAX
brightness) when active. Maximum source current per lamp is 125 mA. Voltage varies with photocell dim-
ming.
2.5.3
Middle Marker Sense
A Middle Marker Sense output signal is available from the PMA450B to certain flight control systems. This
function will not operate during the test mode. This output will go to +4.5 VDC (
1.0 VDC) when a valid
Middle Marker signal is received. This output is J1, pin 39.
