Major Alarm Panel

TM11-5895-932-14&P

(1) Following the circuit path from the AMME

marked LINE and EQUIP. Both monitor jacks are

isolated by 16K resistors from the communication

to the modem through the patch module, there is a

lines to reduce any possible loading from monitoring

separate 12-wire connector for the wires from the

equipment.

AMME, a normal through jack (marked COMP),

(2) Patching for this module is the same as the

another normal through jack (marked MODEM), to

2-wire audio module explained above, that is, a 2-

a separate connector for the 12 wires to the modem.

wire patch cord set into a normal through jack to

A 12-wire jack, marked MON, is also connected to

break the communication line and reroute it to a new

the circuit for monitoring purposes.

path.

(2) During patching operations, one end of a

d. Hi Level DC Patch Modules. The high level dc

patch cord connected to the COMP jack breaks the

patch module is used to patch the high level (120

through connection to the MODEM jack and puts

vdc) teletype signals (output of the DLIU) The

the lines from the AMME in series with the patch

patch module is configured similar to the other 2-

cord. The other end of the patch cord transfers the

wire patch modules; that is, four vertical jacks for

wires to another circuit which would be connected to

the MODEM jack. The connection into the MODEM

each circuit, 24 circuits to the module

(1) Following the line connections to the

jack disconnects the through circuit connection and

puts the patch cord in series connection to the

equipment connections on the diagram (fig. 5-1D),

an arrangement different from the ones previously

modem.

b. 2-Wire Audio Module. The 2-wire audio module

encountered is found. One wire of each circuit pair is

is used in the vf entrance jack field. A module

muted through a monitor jack before connecting to

handles twenty-four 2-wire circuits, using four 2-

the normal through patch jacks. In this case each

wire jacks arranged vertically for each 2-wire circuit.

monitoring jack (MON) is connected in series with

There are two normal through and two monitor jacks

the lines rather than as before, in parallel.

for each 2-wire circuit. A duplex circuit uses two

(2) The patching principal for this module is the

vertical jack sets; one for the transmit line and one

same as previously encountered. The patch cord

for the receive line.

inserted into the normal through jack breaks the

(1) A 2-wire line connected to pins 1 and 2 on Cl

circuit and the patch cord is used to transpose the

(fig. 5-1B), proceeds through the equipment as

wires to another circuit number. Monitoring,

follows: from Cl to the LINE jack; from the LINE

however, is entirely different because instead of a

jack to C2 where it is looped around by P1; from C2

parallel connection, a series one is used. The series

to the EQUIP jack: and then from the EQUIP jack

connection provides a means of connecting a dc

to the equipment side of the line at Cl. Two jacks,

milliammeter in series with the line for measuring

marked MON, are used for monitoring lines con-

and setting the telegraph current.

nected to the equipment and the line jacks.

5-3. Major Alarm Panel

(2) For patching, a 2-wire patch cord is used for

The major alarm panel operates as an indicator for

each transmit and receive line. Connecting to the

remote troubles and centralized, within a single

LINE jack, the patch cord is in series with the line

panel, alarm controls for up to 45 alarm circuits.

side of the patch panel and the equipment side of the

Each alarm circuit condition is displayed by a

patch panel is disconnected by action of the LINE

lighted segment of the front panel, which is also a

jack. To transfer the line to another circuit's

switch used for removing the audio alarm. Each item

equipment line, the second end of the patch cord is

which provides an alarm input to the alarm panel can

inserted into the EQUIP jack of that circuit. This

be designated a major alarm The major alarm

disconnects the line from the equipment in that

conditions are displayed in different colors.

circuit and completes the patch.

a. Considering first the external circuits which

c. Low Level Patch Module. The low level patch

connect to the major alarm panel on figure 5-2, there

module is configured the same as the 2-wire audio

is a possibility of 90 inputs for alarms. Each alarm is

patch modules. That is, there are two normal

signalled by a ground input to pins 1 through 45 on

through and two monitor jacks for each circuit and

the main connector. Pins 46 and 47 are outputs

24 circuits for each module.

(grounds) which go to an audible indicator, causing

(1) Following the circuit shown in figure 5-1C,

it to sound. Other pins on the main connector are dc

the line is connected to the LINE normal though

ground and input power and negative 48 volts direct

jack and the equipment is connected to the EQUIP

current.

normal through jack. Parallel connections from both

the LINE and EQUIP jacks are two monitor jacks

5-3