11. To verify a ground circuit, turn the handcrank on the test telephone,
if the handcrank turned hard and you heard noise on the line, a ground
circuit is on the line (Chapter 11, FM 24-20).
12. A cross circuit occurs when the conductor of one wire line comes in
electrical contact with the conductor of a second or both wire lines
(Chapter 11, FM 24-20).
a. The electrical contact of crossed pairs on local-battery lines
unbalances both lines. The unbalance tends to cause inductive cross talk.
The single electrical connection itself does not provide a closed voice
circuit, except in the unlikely event that both conductors of each pair are
crossed.
b. The result of cross on two common-battery telephone lines will also
cause cross talk; but, there may also be a permanent signal on the line.
13. Cross talk may be verified by connecting the wire line to the test
telephone and lifting up on the handset (paragraphs 2-3d and 3-2c, TM 11-
5805-201-12).
a. Place receiver end of handset to your ear and operate the PRESS-TO-
TALK switch by pressing down on the switch.
b. Cross talk is present when you hear your transmission with the other
line transmission.
14. Routine test is performed on line to maintain proper maintenance at
slack or light traffic over circuit.
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