Toa EXES-6000, Operating And Troubleshooting

Page: 38 / 60

The tone burst signal sent to the dial receiving
section of the Tl in exchange B via a tie-line link is
then transmitted to the CP through the BPF
(Band-pass Filter), amplifier and rectifier (Amp. &
Rect. in the Figure), after being converted into the
original dial pulse stream by the dial pulse
converter. The CP processes the dial pulse
stream, and orders the HC to turn on or off the
time division switch for the speech path.
In Fig. 38, a red line shown the voice signal flow
from station No. 200 to station No. 470, and a
green dotted line represents a dial pulse stream
flow from station No. 470 to station No. 200.
2. Voice Signal Flow
See red lines in Fig. 38.
Assume that conversation flows from station No.
200 to station No. 470.
In exchange A,
(1) the voice signal flow when both Tx
1
and Ty
1
close:
Station No. 200 ... Tx
1
... HW-T ... Ty
1
... link No. 1
(voice is held)
(2) the voice signal flow when both Rx
2
and Ly
1
close:
Link No. 1 ... Rx
2
... HW-R ... Ly
1
...Tl
The PAM signal is demodulated into the analog
voice signal in the Tl unit, which passes through
tie-line link No. 1 and flows to the data receiving
(audio signal transmitting) section of the Tl in
exchange A. It is then transmitted to the data
transmitting (audio signal receiving) section of the
Tl in exchange B.
In exchange B,
(1) the voice signal flow when both Lx
1
and Ty
1
close:
Lx
1
... HW-T ... Ty
1
... link No. 1 (voice is held)
(2) the voice signal flow when both Rx
2
and Ry
1
close:
Link No. 1 ... Rx
2
... HW-R ... By
1
... Station No.470
A red dotted line in Fig. 38 represents the voice
signal flow from station No. 470 to station No.
200.
*
The signal that flows in the tie-line link is not
the PAM signal but the analog voice signal (base
band). The on/off timing of time division switch for
forming the speech path in exchange A is com-
pletely independent of that in exchange B.
A single Tl unit has 8 each of data transmitting and
receiving sections, meaning 8 tie-line links. When
one (1) Tl unit is mounted on each exchange,
there are 8 speech links between exchanges A
and B.
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