Cockpit Communications Using V+

feature author: Paul Halliday

The cockpit communications requirements for the Beech 1900D simulator were not that rigorous. There were two pilot stations, each with two microphones (regular headset and oxygen mask), an Instructor station, and an Observer station. The voice communications for the simulator were set up using the following requirements. 

1. There are four stations: Pilot, CoPilot, Instructor, and Observer.

2. The Pilot and CoPilot voice communications function as in the real aircraft.

3.  The Instructor and Observer always hear the Pilot and CoPilot.

4. When either the Pilot or CoPilot use a PTT, the volume of their voices will increase to full in the Instructor and Observer’s headsets. Otherwise the volume of  their voices will remain at half.

5. If the Hot Interphone switch is on, the volume of both the Pilot and CoPilot’s voices will increase to full.

6. The Instructor may transmit to the Pilot, CoPilot, both, or neither.

7. The Instructor’s microphone is always transmitting to the Observer’s headset at a half-volume side-tone.

8. The Instructor’s microphone is always transmitting to the Instructor’s headset at a half-volume side-tone.

9. The Observer’s microphone is always transmitting to the Instructor’s headset at a half-volume side-tone.

10. The Observer’s microphone is always transmitting to the Observer’s headset at a half-volume side-tone.

Controls that affect communications are shown in Table 3.

Table 3 .  Communications Controls

For the most part, the designs that follow use simple logic to combine these controls in such a way as to provide signals to the outputs, which are controls ports for the FX-30 mixer. This mixer is a Commercial-Off-The-Shelf (COTS) product manufactured by SimPhonics, and is composed of two separate cards working together. It plays an integral part in the processing of voice signals and signals coming from players in the NAV_DME, Marker, ADF, and ATIS V+ designs discussed in this article. A custom patch panel and cable had to be produced for the Beech 1900D simulator. The patch panel was manufactured by TDI, and SimPhonics manufactured the cable.

I’ve been involved in building several simulators and when it comes to voice communications for these simulators, it has always been a very difficult, one-of-a-kind problem to solve. This doesn’t have to be a nightmare! With the Audio 16 card coupled with the ISA-30 DSP, a 16 by 16 input/output matrix allows you to direct any of 16 separate inputs to any of 16 separate outputs. And it’s all made simple by… you got it – V+.

For the Beech 1900D simulator, we only needed 12 of the 16 available FX-30 inputs, and 6 of the available 16 FX-30 outputs for taking care of the voice communications requirements. The FX-30 allocated channels for the inputs are shown in Table 4. Note that players dealing with nav audio are treated as inputs to the FX-30 (they come out of the player and into the FX-30). The output of the ATIS system is also an input to the FX-30.

Table 4.FX-30 Inputs

Table 5. FX-30 Outputs

The FX-30 allocated channels for the outputs are shown in Table 5. Each FX-30 output has 16 inputs and one master gain associated with it. These 17 items per FX-30 output are treated as output ports in a list shown in Figure 46 (you need to select the DSP 1 Output I/O Device at the top of the Ports window to see the list shown in the figure).

Figure 46.  DSP Output Ports

These two cards constitute the FX-30 system, which is part of the SimPhonics computer system.