Patching Operations at Dc Patching facilities

TM 11-5895-1012-10

panels. On the count-of-three, all loose plugs are set

(2) Place the plugs on the other end of the patch

into the jacks simultaneously.

cords loosely into the channel 5 REC EQU and TRANS

(4) On the equal level patch panel, terminate the

EQU jacks.

channel TRANS LINE with a 600-ohm termination

(3) Establish voice contact between the Technical

plug set into the TRANS LINE jack.

Controllers at Station A and Station B.

(4) One Technical Controller will take charge and

4-21. Patching Operations at Dc Patching

on a prearranged signal, usually the count-of-three, all

Facilities

loose plugs are set into the jacks simultaneously.

a. General. The jackfields in the Dc patch bays are

(5) The transmit aide of the patched off channel

employed to gain access to Dc circuits for monitoring

(in this case channel 5) is terminated with a 600-ohm

purposes and to perform circuit rerouting, test

termination plug set into the TRANS LINE jack.

measurements and restoration of service by equipment

c. Transfer of an Active (Circuit to a Spare Cable

substitution. Representative patching operations are

Pair (fig. 4-2). The situation requires that for test or

given in b, c, and d below. A cut-key is provided to

maintenance purposes, the active circuit or channel 5

interrupt a telegraph channel for tactical considera-

be transferred to the tail segment cable pair for spare

tions, or for the correction of an operational fault

channel 2. This patch is made at the primary patch

condition at either the subscriber station locations. In

panel (fig. 2-15) at Station A and the Patch and Test

the event a condition exists which caused the teletype-

Facility patch panel at the other end of the cable. The

writer equipment at the locations to run open,

patching operations are the same at both ends of the

the Technical Controller activates the appropriate cut-

cable. Only the patching operation at the TCF is cov-

keys to isolate the subscriber loops affected and ap-

ered below.

plies hold battery to the subscriber teletypewriter

(1) Place two patch cord plugs loosely into the

machines. Upon correction of the condition, the cut-

channel 2 REC LINE and TRANS LINE jacks.

keys are restored to normal position. When a cut-key is

(2) Place the plugs on the other end of the patch

activated, the following actions occur: the telegraph

cords loosely into the channel 1 REC EQU and TRANS

circuit is interrupted, hold battery is applied to the

EQU jacks respectively.

channel terminating unit and the associated cut lamp

(3) Establish voice contact between the TCF and

indicator is activated. This cut-key is also employed for

the PTF.

scheduled interruptions of circuits such as those en-

(4) The Technical Controller will take charge and

countered with high frequency radio systems.

on a prearranged signal, usually the count-of-three, all

b. Transfer of a Dc Circuit to a Spare VFCT Channel

loose plugs are set into the jacks simultaneously.

(fig. 4-4). The situation requires that for test or main-

d. Substitution of Line Conditioning Equipment

(fig. 4-3). The situation requires that for test or main-

tenance purposes, a teletypewriter circuit is to be

transferred from VFCT channel 1 to a spare or lower

tenance purposes, the spare line conditioning equip=

priority channel 2. The patching operation is

ment (channel 2) be substituted for the active line con-

ditioning equipment (channel 5). Before the patch is

accomplished at the equal level dc patch panel at both

the local and distant station. Coordination is required

made, check the spare channel line conditioning equip

ment to make sure it is configured the same as the

so that the patch is made simultaneously at both ends

active channel. The patching is accomplished at the

of the communications path to preclude loss of large

primary and equal level patch panels (fig. 2-15) at Sta-

blocks of record traffic.

tion A. Since the patch panels are normally physically

(1) Place two patch cord plugs loosely into the

separated, two Technical Controllers are needed to

channel 2 REC LINE and TRANS LINE jacks.

perform the operation with minimum interference to

(2) Place the plugs on the other end of the patch

the users. The procedure described below is the same

cord loosely into channel 1 REC EQU and TRANS

at both patch panels.

EQU jacks respectively.

(1) At the equal level patch panel, place two patch

(3) Establish voice contact with the distant sta-

cord plugs loosely into channel 5 REC LINE and

tion. One Technical Controller will take charge and on

TRANS LINE jacks. Place the plugs on the other end

a prearranged signal, usually the count-of-three, all

of the patch cords loosely into the channel 2 REC EQU

loose plugs are set into the jacks simultaneously (at

and TRANS EQU jacks respectively.

both ends of the circuit).

(2) At the primary patch panel, place two patch

c. Transfer of a Dc Circuit to a Spare Digital Line

cord plugs loosely into the channel 2 REC EQU and

Interface Unit (DLIU) (fig. 4-5). The situation requires

TRANS EQU jacks. Place the plugs on the other end of

that for test or maintenance purposes, a teletypewriter

the patch cords loosely into the channel 5 REC LINE

circuit is to be transferred from the DLIU associated

and TRANS LINE jacks respectively.

with channel 1, the normal channel, to the spare chan-

(3) Establish voice contact between the two patch

nel 2 DLIU. Before the transfer can be made the spare

4-7