TM 55-1930-209-14&P-1
Section IV. Telephone system
5-14 Description. The telephone system is an intercom/paging system used for communicating between a system
operator in the dayroom and 12 crew telephone stations. The system can also be used for communicating between crew
telephone stations. Twelve telephone stations are connected to 21 headset stations that are serviced by 14 buzzers, 3
strobe lights and 10 telephone set stowage boxes. Their locations, station numbers, and equipment are listed in Table
5-4.
The telephone system shown in Figure 5-13 consists of the components listed in Table 5-5. Equipment specifications,
maintenance information, and manufacturers' service manuals are contained in TM 55-1930209-14&P-12.
5-15 Capabilities. Telephone system provides two-way conversation capability between a dayroom system operator
and crewmembers at 21 telephone headset stations or between crewmembers at these stations.
5-16 Special limitations. Paging can be done only from the dayroom telephone station selector. However, after a
telephone headset has been plugged into a headset station jack receptacle, a crewmember can talk through the speaker
to page dayroom system operator, talk to dayroom system operator or talk to another headset station.
5-17 Performance characteristics
a.
Telephone power amplifier
Input impedance
80,000 ohms minimum
Output
2 watts 24 Vdc and 16 ohms
Gain
32 dB
b.
Telephone speaker
Input impedance
8 ohms
c.
Telephone power control module
Power input
24 Vdc nominal
Output current
0.5 A
d.
Telephone headset
Microphone
M-1/dc Amplified Dynamic, nominal 100 ohms
Earphone
Dynamic, nominal 300 ohms
Noise capacity
125 dB
e.
Strobe light
Input power requirement
120 Vac, 50/60 Hz
Light output
500,000 candlepower, 60 flashes/min, white
f.
Buzzer
Input power requirement
120 Vac, 50/60 Hz
5-23
