Figure 5-23.--Sound-powered magneto call circuit 2EM.

Figure 5-23.--Sound-powered magneto call circuit 2EM.

CIRCUIT MJ - MULTIPLE-TALKING AND

avoid the need of setting the station selector switch to

SELECTIVE RINGING CIRCUIT

the ANSWER position, which is required to use the local

call signal station handset. Figure 5-24 is an elementary

wiring diagram of an MJ circuit.

Circuit MJ provides a means of communication

with more than one conversation on the circuit

CALL AND SIGNAL CIRCUITS

simultaneously, as well as providing selective ringing at

MAINTENANCE

each station. In addition, the sound-powered telephone

and ringing circuits are combined to provide one

common talking circuit between all stations. Up to eight

You should accomplish preventive maintenance of

separate conversations are possible at one time. The

call and signal circuits according to the applicable

circuit may be used with any particular sound-powered

MRCs. Corrective maintenance will usually consist of

circuit where its capabilities would be advantageous.

isolating shorts, grounds, and opens in the circuits and

repairing or replacing the audible and visual signal

IC/D call signal stations are used with circuit MJ.

devices used with the circuits.

The internal wiring of each call signal station is revised

and a relay and diode assembly is mounted on the

selector switch of each call signal station. When the

SOUND-POWERED TELEPHONE

relay is de-energized, its contacts complete the circuit to

SYSTEM AN/WTC-2(V)

the local handsets at all call signal stations on the circuit.

When a caller cranks the hand-operated magneto

The AN/WTC-2(V) sound-powered telephone

generator at the calling station, it energizes the coil of

system is installed on some naval ships. This system

the relay at the called station. The contacts of the relay

replaces the existing EM and MJ call and signal circuits.

then close to complete the circuit to the howler at the

The system is designed for interior shipboard use and,

called station. At some call signal stations on the circuit,

along with the sound-powered telephone circuits

extension handsets are provided for convenience in

d i s c u s s e d earlier, provides two-way voice

answering incoming calls. The extension handsets are

communication between shipboard terminal stations.

connected to the "home station" circuit MJ wires to

You can signal and talk on the same cable. The system

5-25