Oki OKIOFFICE84 Maintenance Manual page 311

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.
Line
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.
CN2
(1/2)
A
TEL1
K
S1.1~2
A '
TEL2
CN2
(2/2)
SR
8
A "
7
TEL
CN1
CML:ON
1
LINE
AR , AR
1 2
arresters
TEL
B
Remote control
A
B
RL
7
F
F
IC OFF-HOOK
2
Detector
IC D
1
I SW
S1 - 3~6
Ring Detector
C
C31 R590
2
Loop
Current
B
Detection
RL3 MUTE
DB1 IC5 9
3
DP
DC
circuit
4
SW
H
Block diagram for Parallel Pick Up Path.
A3 - 41
FAX (FX—048 etc)
To modem
SW
SW
J
S4
Impedance
matching
E
5
NT
T1
C11
A
IC7
RL6
0
MUTE
Q3
S3
Parallel Pick Up
CN3
OH2
RI
G
CN15 ~
CN45
S
6
to Modem
Receiving
RP
sensitivity
Adj
R
40672201TH Rev. 3