Call Hold

To create a loop, four or more point-to-point,

2. Depress the press-to-talk switch to establish

conference calls, or both must be in progress at the

communications on the net.

same time and a particular and predictable relationship

3. When finished, disconnect the headset-chestset

must exist among the station numbers of the called

from the jack or jackbox and stow it.

stations. The numbers of the calling stations are

immaterial since the cable pairs carrying the calls are

Call Hold

those assigned to the called terminal station. The called

station is permanently connected to those pairs that carry

The call hold function is used by a terminal station

the call, while the calling station connects itself in

that has originated a call and desires to maintain

parallel to those pairs by the use of the station selector

communication with the called station while answering

switch.

an incoming call. To perform the call hold function, you

When a loop is formed, the operators of the affected

should use the following procedure:

stations will simultaneously hear all conversations

1. Inform the called station that you have an

among the stations involved in the loop. The

incoming call, and tell the called station to stay on the

conversations will be at relatively high audio levels,

line while you answer the call.

making normal communications among these stations

impossible.

2. Answer the call according to normal procedures

by setting the PLACE CALL/ANSWER switch to the

The only way to break a loop after it has formed is

ANSWER position.

to end one of the calls. The press-to-talk switches on

3. When you have finished with the incoming call,

both handsets of the stations involved must be released

set the PLACE CALL/ANSWER switch to the PLACE

to end the call. NEVER tape down the press-to-talk

CALL position and continue with your original call.

switch of a handset. A taped down switch will act as a

continuous call even when a call is ended.

Executive Override

There is a caution label plate on the front cover of

each terminal station to caution operating personnel

When a station has received a call and is talking to

against excessive traffic.

the calling station at the time a second call is received,

the second call is considered an override function. The

SYSTEM MAINTENANCE

call hold function cannot be used in this case.

Preventive and corrective maintenance for the

COMMUNICATION INTERFERENCE

system should be accomplished according to the

applicable MRCs and associated technical manual(s)

Communication interference while making

for the system.

point-to-point, conference calls, or both may occur due

to cross talk and looping.

VOICE TUBES

Cross talk

Voice tubes are installed aboard ship in addition to

the sound-powered telephone system to provide another

Cross talk is the effect created when an AC signal

way for transmitting information between designated

from one lead in a cable induces a small voltage into the

stations. The voice tube is used to transmit voice orders

adjacent lead. Crosstalk, while usually always present,

and information over short distances by nonelectrical

is at a relatively low audio level and will be heard as a

means. Voice tubes are made of 3-inch brass,

faint background conversation during a call.

thin-walled tubing fitted with mouthpieces at each end.

Voice tubes are installed between the following stations

Looping

aboard ship as applicable:

Looping is an undesirable and unintentional

Surface Ships

formation of a complex series-parallel circuit among

From the pilothouse (helmsman's station) to the

stations that are simultaneously busy. This is a result of

navigation bridge wings (port and starboard)

a direct connection between terminal stations when an

From the pilothouse (helmsman's station) to the

excessive number of simultaneous point-to-point calls

exposed conning station (top of pilothouse)

are being made.

5-32