The Model 438 Audio Control Amplifier is a remotely controlled, electronic unit which operates upon command from switches and potentiometers in the cockpit. The amplifier is capable of switching and separately controlling the volume for up to 12 receiver inputs. It also switches five sidetone inputs and an interphone line.
Version 483-003 provides interphone operating levels for 8-station interphone system (37ohm interphone line) with more interphone audio to the speaker and headphone than the base model. Also increases the receiver levels to compensate for increased load on the receivers by multistation Model 438's.
友情提醒：件号：438-003 相关介绍完善中 / 部分技术参数正在核实，当前信息仅供参考，最终订货请以实际件号、原厂资料及 IPC 手册为准。
规格：
Operating mode pin numbers:
P40-18 Speaker switch
P40-6 INPH hot switch
P40-14 INPH to speaker switch
P40-16 PTT switch
P40-11 Voice switch
P50-6,7,9,10,11,12,13,23,24,27,28,29 Receiver switches
P50-22 PA key
Test.
特征：
Two unswitched and unmuted inputs for aural warning input and an auxiliary input
Headphone and selected speaker outputs are isolated
Cockpit voice recorder output from headphone and interphone microphone audio
Microphone audio can be recorded on the cockpit voice recorder at all times
Pilot select COMM output produces a summation of COMM1 through COMM 4, DME 1 and 2, and the MKR 1 and 2 receiver inputs
Compatible with the model 240, 250, or 251 PSC audio input channel (or equivalent)
Speaker channel is powered through an internal fuse separate from the headphone channel
Receiver and operating modes are electronically switched
Electronic attenuator in each of the 12 receiver input channels
30 dB attenuator range control cockpit volume potentiometer
Selective voice or code filtering on four receiver audio inputs
Voice activated switch in series with microphone input
