Orderwire and Direct Current Path

TM 11-5820-695-35

d. Orderwire and Direct Current Path (fig. 5-7 and 5-

zero is sent to alarm monitor 1A12A5 (or 1A12A15) to

indicate the presence of the pcm signal. If the pcm

29) The from cable orderwire (FRCXOW) and direct

signal fails, A6 times out and the output goes to logic

current signal are separated from the pcm signal m

zero Q1 is then cut off, lamp DS1 goes out and the

cable digital regenerator 1A12A2 (a above). The two

output signal (ICRLFAIL) is at logic one.

signals are then routed to the primary of transformer

1A12A12A1T1

(3) When CABLE LOOP TEST switch

1A12A12A1S1 is in NORMAL position, the output signal

(1) The ow portion of the signal is coupled to

of inverter A3B is logic zero, and the output signal of

the secondary of transformer 1A12A12A1T1 and the

cable loopback sample gate A3C is logic zero. When

THRU OW RECEIVE LEVEL ADJ potentiometer to the

CABLE LOOP TEST switch is in TEST position, the

cable-to-radio circuits portion of amplifier 1A12A6 The

output of A3B provides a logic one at one input of A3C

THRU

RECEIVE

LEVEL

ADJ

control

The other two inputs are the pcm signal (typical

(1A12A12A1R1) on the front panel of digital data

waveform B, fig. 5-32) and the clock signal (waveform

modem 1A12 is used to set the ow input level to

C, fig 5-32). Whenever both signals (waveforms B and

1A12A6.

C) are at logic one, the output signal of A3C is logic zero

(waveform A, fig. 5-32) Thus, the output of A3C is logic

(2) The direct current portion of the signal from

zero whenever the pcm signal is logic one but the

1A12A2 is routed to the radio-to-cable circuits of 1A12

duration of the logic one is reduced to 80 nanoseconds

through the primary of transformer 1A12A12A1T1,

by the 80 nanosecond clock pulses The output of A3C

inductor 1A12A12A1Ll and capacitors C1 and C2 of the

(OCLPCM) is applied to the cable system through radio

orderwire filter, and a jumper connection through FAULT

digital processor 1A12A10 (or 1A12A16) in the radio-to-

LOCATOR POWER SUPPLY INTERCONNECT J20

cable circuits and is used to test the cable system.

and plug P3 on top of electrical equipment cabinet lA15.

The from cable ow (FRCXOW) signal is removed from

the direct current path by the orderwire filter. The direct

current path is connected

Change 2 2-14.1