Oki OKIOFFICE84, Maintenance Manual

Page: 311 / 519

Parallel Pick Up
A3 - 41 40672201TH Rev. 3
4.5 Outline of Parallel Pick Up
Parallel pick up is a function that controls a fax (to make a fax in receive mode) from a
telephone set connected parallel to a fax. The two possible parallel connections of
telephone sets A and B are shown in the figure.
Remote control: To control a fax from telephone set A.
Parallel Pick UP (PP): To control a fax from telephone set B.
• Why a PP function is needed!
As shown in the following block diagram, telephone sets B, A, A' and A'' are connected
to a telephone line.
Since A, A' and A'' are connected to the line via fax, off-hook status of any of the
telephone sets can be detected by the OFF-HOOK Detector 16 in the block diagram.
However, off-hook status of telephone set B cannot be detected by the fax side.
• PP Control
When a normal ring arrives at the fax from the line, the CML 7 turns on resulting in the
formation of an AC loop via circuit 13. The AC loop makes it possible for the modem to
detect the AC signals. If a user hooks up telephone set B after the first ring and enters
the MF 2-digit special code in order to make the fax in the receive mode, then it
becomes possible to detect the MF signals along that route.
A
B
To modem
Line
SW
FAX (FX—048 etc)
Remote control
AR
1
, AR
2
arresters
TEL1
TEL2
LINE
1
DB1 IC5 IC7
DP
DC
circuit
B
RL3
4
3
SW S3
H
MUTE
0
9
CML:ON
7
8
SR
I
SW
S1 - 3~6
Ring Detector
C31 R590
C11
T1
E
Impedance
matching
NT
5
G
CN15 ~
CN45
Receiving
sensitivity
Adj
RL6
A
R
RP
S
RI
OH2
SW
S4
J
IC
1
D
IC
2
F
F
RL
7
K
S1.1~2
Q3
C
to Modem
CN3
6
MUTE
OFF-HOOK
Detector
TEL
TEL
CN1
CN2
(2/2)
CN2
(1/2)
2
Loop
Current
Detection
A
A ’
A "
B
Block diagram for Parallel Pick Up Path.