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10.3.0 1200 BPS INTEGRATED MODEM
10.3.1 Transmit Level Adjustment Using
db Meter PIN 453545
1
or
db Adapter PIN 1749299
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DO
0
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0
db Meter
PIN 453545
1
SET INSTRUMENT TO
, 8 mADe POSITION
IBM
db
ADAPTER
800[[JBRIDGE-,
VOLUME
~ ~
_4-;8°-20 -10 °
EOT_
~TEST
-50
OFF
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f~
@INPUT@GND
~
db Adapter
PIN 1749299
Use the db meter or adapter to adjust both leased
line and switched networks. For a wider range of
adjustment, there is a 0 db jumper on the transmit
card. The 0 db jumper must be removed for World
Trade leased line installation.
Jumper on
=
Full adjustment range
(U.S.A. and Canada)
Jumper off
=
Adjustment to approximately
-2 db maximum (WT use).
Direct attachment to a leased line normally requires
a 0 dbm transmit level. (In WT, adjust to a mini-
mum db value; in the U.S.A. and Canada, adjust to
o
db.) If attachment is by a switched line with
CBS automatic data coupler, or equivalent, adjust
the transmit level to the value marked on the
common carrier equipment.
To set the appropriate transmit level, use one of
the following procedures:
1
Branch office tool
Leased Board
Gate C
•
6
•
5
4
Leased Line:
1.
2.
3.
4.
5.
6.
7.
8.
9.
Turn off system power.
Disconnect communication line plug.
If you are using the db meter, insert the plug
in the TRANS/R EC jack of the db meter. If
you are using the db adapter, connect the
meter leads to the wide pair of plug prongs.
If you are using the db meter, place 2W-4W
TRANS/R EC switch in TRANS and attach a
jumper from line terminals on cover to line
terminals on meter.
Place the BRDG-600 {324} switch in the 600
position.
Connect pins 4, 5, and 6 together (with
jumper
PIN
5159491) on the modem board
(see leased board illustration). This un-
damps the transmitter and turns on 'request
to send'.
Turn on system power.
While reading dbm scale on meter, adjust R3
potentiometer on the transmit card (Cl) to
the correct level. (In WT, adjust to a mini-
mum db value; in the U.S.A. and Canada,
adjust to 0 db.)
Remove the board jumper that was installed
in step 6.
Switched Board (U.S.A. and Canada)
Gate C
•
11
o
10
•
9
•
8
•
7
6
5
4
10-4
Switched Lines (U.S.A. and Canada):
1.
2.
3.
4.
Turn off system power.
Disconnect cable from modem (socket E2).
On db meter, place the BRDG-600 (324)
switch in the 600 position.
Remove automatic answering interface card
(socket B2).
5.
Connect pins 6, 7,8, and 9 together (use
PIN
5159491, see switched board illustra-
tion). This causes the DT to be grounded,
'request to send' to come on, and the trans-
mitter to be undamped.
Attach a jumper from pin 4 to pin 5 (use
jumper
PIN
816645) to turn on 'data set
ready'.
6.
Connect pin 10 to black line terminal on
db meter.
7.
Connect pin 11 to red line terminal on
db meter.
8.
Turn on system power.
9.
While reading dbm scale, adjust R3 poten-
tiometer on the transmit card (Cl) to the
correct level. (Correct level is indicated on
cover of CBS or equivalent type cover.)
10.
Remove the board jumpers that were
installed in step 5.
11.
Replace card in B2 and cable in E2.
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