Section II. PATCHING OPERATIONS - TM-11-5895-932-14-P0046

TM11-5895-932-14&P

company. A list of equipment manuals is included

troubleshooting is brought about in an effort to

in appendix A.

restore communications, a faulty or incorrect

c. Reference Publications Reference publications

diagram can add hours onto the time of the

which should be included in the station records are

communications outage. Simple fault location

those manuals, documents and other data which

becomes a long drawn out procedure when a faulty

provide background, standards, or testing in-

drawing complicates it even more. Plant-in-place

formation. A list of these types of documents are

records must be accurate and complete prior to

included in appendix A.

time of the failure which interrupts communications.

d. Locally Prepared Data. Locally prepared

b. Equipment Manuals. The equipment manuals

data which is included as part of station records

which come under the heading of station records

are the patch board labels. labels on the power

are all manuals, commercial and military, that

load centers denoting circuit breaker application,

cover the individual items of station equipment.

any simplified patching diagram placed on patch

These items of equipment are either mounted in a

bays, and trouble logs. In general, any instruction

rack or, in the case of the red/black isolators, are

or aid to operation and troubleshooting of the

whole equipment racks. They are generally not

equipment can be considered part of the station

built by the installation/engineering agency but

procured as a separate item from a separate

records.

Section II. PATCHING OPERATIONS

3-4. Patching, General

(4) Technique. Develop

the

habit

rechecking your cord and plug positions just prior

a. The communication lines or paths that run

to completing the patch. Set the patch up with the

through the PTF are provided with patch boards

cable plugs only loosely set into the patch jacks.

which are connected between equipments and at

Then recheck the signal flow prior to plugging in

the line entrance and exit points. The patch boards

the idle sections: then plug in idle section fully;

are equipped with jacks that allow for either a

and finally complete the patch by setting in (or

parallel circuit connection for monitoring (MON) or

throwing) the plugs to the active line section

a series connection which opens the circuit and

simultaneously.

connects another circuit in its place. The series

(5) Prohibitions. Although the PTF was

jacks on the patch boards are used for testing and

designed to minimize the chances that red and

temporarily

circuit

paths for

rearranging

black circuits can be patched together, operators

troubleshooting and for the restoration of com-

should especially be alert to this possibility. Red

munications.

circuits must not be patched to black circuits. The

b. Successful patching requires knowledge of the

electrical Isolation of circuits provided by the

circuits and equipments, a technique that comes

red/black isolator cabinets must not be ignored.

from practice, and adherence to certain

precautionary measures.

3-5. Patching for Equipment Substitution

(1) Circuit Knowledge. Knowledge of the

Examples of typical patch cord connections are

circuits and the type of signals they handle is

provided here to illustrate connections for patch-

essential for proper patching. Like signals have to

ing-in substitute equipment. PTF personnel

be patched to like signals. Signal paths must be

should examine the diagrams to understand the

maintained, i.e., output from one item of equip-

principles involved.

ment must go into the input of the equipment

a. Modem Substitution (fig. 3-1). This patch

patched to.

removes the modem on circuit number 2 and

(2) Operational Spares. Operation spare lines

substitutes a spare modem from circuit number 21.

and equipment must be maintained. Standby

At bay 1.7, a multicircuit patch cord is connected

equipment maintained in these spare circuits are

from the COMP jack of channel 2 to the MODEM

used when patching around a defective item.

jack of channel (circuit) 21. On the vf frame and

(3) Precautions. Patches should not be made

patch bay 1.9, two 2-wire patch cords connect the

haphazardly, without thought to the interruption

modem transmit and receive lines from circuit 21

of traffic. Always know what is on the circuit to be

to the lines of circuit 2.

interrupted. When possible, coordinate with others

affected so that when circuits are patched no

traffic is being passed.

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