PS Engineering PMA7000B Specifiche Scaricare il pdf (Pagina 11)

PS Engineering

PMA7000B Series Audio Selector Panel and Intercom System

Installation and Operator’s Manual

200-780-0005 Page 2-4 Rev. 11, February 2015

2.4.5 Communications Push-to-Talk

An important part of the installation is the PTT (Push-To-Talk) switches that allow the use of your aircraft

communications radio for transmissions. There are three typical configurations that can be used. Select the

case that best fits the installation. Only the person who presses their PTT switch will be heard over the ra-

dio. If the pilot and copilot both use the PTT, the only pilot position has access to the radio. The pilot posi-

tion will have PTT control regardless of the mic selector switch or copilot PTT when the PMA7000B is in

the OFF/EMG mode.

CASE I: PTT is built into both pilot and copilot yokes.

CASE II: PTT is in pilot yoke only. This configuration requires a modified external PTT switch plugged

into the copilot's microphone jack. (See Appendix A). When the copilot's PTT is pressed, the intercom

switches the microphone audio from pilot to copilot mic.

CASE III: No built in PTT. This requires two built in PTTs to be installed, or modified external PTT

switches to be used. Modify external PTT as required. See Appendix A.

2.4.6 Audio Panel interface

The PMA7000B is designed to interface with standard aircraft avionics, and presents a 500 receiver im-

pedance. For best results, a twisted-shielded cable is recommended from the avionics audio source to the

audio panel, with the shield grounded at the audio panel end.

Some avionics do not provide a separate audio low, and may introduce additional electrical noise into the

system. For best results, connect the audio low from the audio panel to the radio ground, using one conduc-

tor of the twisted-shielded cable.

2.4.6.1 Speaker Load

The PMA7000-series contains a speaker amplifier. Some units with internal speaker amplifiers, such as the

King Radio KX170-series, require a resistive load to prevent damage if their speaker amplifier is not used.

Connect the speaker output from the unit to the load input on the PMA7000B (J1, pins 19 and L, 16 and M.

The speaker load is 16 , 3W.

2.4.6.2 Fail Safe Connection

The PMA7000B connects the pilot microphone and headphone directly to COM 1 input when power is re-

moved. The headphone failsafe is the RIGHT channel, connected to the TIP of the headphone jack, to be

compatible with monaural headphones. Unswitched input #1 (Bottom Connector pin T) is also provided to

the pilot headset, right channel, in fail-safe.

NOTE: The pilot headphone MUST be wired in accordance with Appendix C, Bottom connector Pin 3 to

Pilot headphone tip (right) to ensure proper failsafe operation. Verify failsafe operation in accordance with

Section 2.11.2, step 3.

2.4.7 Com 3 Duplex (TEL) Function for Cell Phones

As installed in the standard configuration, the PMA7000B Com 3 function operates conventionally. Pushing

the Com 3 Xmt button places the receive audio from Com 3 in the headset and applies the pilot or copilot

microphone to the Com 3 when the appropriate PTT is activated.

If J2, Pin J is connected to aircraft ground, the PMA7000B is forced into Com 3-Duplex mode. Copilot and

passenger audio as selected by hook switches are provided to the COM 3 output, the PTT for Com 3 is inac-

tive, and audio from Com 3 is presented to the headset. This allows a telephone-like audio interface.

In this mode, the COM 3 input and output is compatible with many cellular telephones utilizing the hands-

free headset interface. A 1/8" or 3/32" jack can be installed on the aircraft panel, which is interfaced with

the PMA7000B as shown below. To connect the cellular telephone to the jack wired in to COM 3, a patch

cord is required. This patch cord is available from PS Engineering under P/N 425-006-7026 (3/32" to

3/32"). A 1/8” to 3/32” adapter cable is P/N 425-006-2535.

1 2 ... 6 7 8 9 10 11 12 13 14 15 16 ... 35 36

Commenti su questo manuale

Nessun commento

PS Engineering PMA7000B Specifiche Pagina 11

Commenti su questo manuale

Prodotti e manuali riguardandi Sistemi di interfono PS Engineering PMA7000B