TM 11-580-356-34-1
parallel to binding posts E5-E6. The output sig-
to lock the receive loop in mark hold, and con-
tacts S2-4-6 close to reset multivibrator A2Q8-
nal path is from T8 through C15, S5C-5-7 and
Q9 via emitter follower A2Q6.
S5C-8-1 to E5. The return is E6 through
S5B-1-3, S5B-7-5, and S4A-8-7 to T8. The in-
g. Break-In Circuit (Detect). An incoming
put signal path is from E5 through S5C-1-3 to
1180-Hz break-in signal couples through the vf
T2. The return is from T2 through C18, SIA-
interface network from binding post E5 through
2-1 and S5B-3-1 to E6.
S5C-1-3, S5C-7-5, and C15 to T3. The return is
(3) Local telephone. With S5 set to TEL,
from T3 through S4A-7-8, S5B-5-7 and S5B-3-
E5 connects to E3 through S5C-1-4 and E6 con-
1 to E6. The 1180-Hz signal developed at the
nects to E4 through S5B-1-4.
send circuit side of T3 couples through 1180-Hz
f. Break-In Circuit (Initiate). When BREAK-
(pass) filter Z1, emitter follower A2Q1, dc am-
IN switch S2 is depressed, contacts S2A-10-12
plifier A2Q2-Q3, and emitter follower A2Q4 to
make to lock oscillator A1Q4 in the 1180-Hz
rectifier A2CR1. The 1180-Hz signal produces a
hold condition. The 1180-Hz hold signal couples
dc level at the output of A2CR1. The level
through the telephone channel to the distant TH-
couples through dc amplifier A2Q5 to delay in-
22/TG. Note that while S2 is depressed, contacts
tegrator A2CR2. The resultant transition at the
S2-7-8 open the send loop, contacts S2-1-3 close
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