3.0 CONFIGURATION
The Model 2702 features configuration capability via hardware
switches . This section describes all possible hardware switch configu-
rations of the Model 2702.
3.1 DIP SWITCH CONFIGURATION
The Model 2702 has eight internal DIP switches that allow configu-
ration for a wide range of applications. The eight switches are
accessed by opening the plastic case with a small screwdriver. Figure
1 (below) shows the location of the DIP switches on the bottom of the
printed circuit board.
The Model 2702 DIP switches (SW1, SW3 & SW4) can be config-
ured as either “On” or “Off”. Figure 2 (below) shows the orientation of
the DIP switches with respect to ON/OFF positions.
Default positions for Switches SW1, SW3, and SW4 are shown in
the table on the following page. Descriptions of each switch follow the
table.
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Figure 1.
Model 2702 bottom view, showing location of DIP switches
DIP Switches
OFF
ON
Figure 2.
Close up of DIP switches showing ON/OFF positions.
NOTE: Switches SW2, SW5, SW6, SW7, and SW8 are not used.
Switch SW1: Line Coding
Use Switch SW1 to control the Network Line Coding options. Set
these options to be the same as the Line Coding given to you by your
Service Provider. If you are using two Model 2702s together as short
range modems, set both units identically.
SW4
Line Framing & Coding
Off
HDB3
On
AMI
Line Coding Options:
High Density Bipolar 3 (HDB3): In HDB3 coding, the transmitter
deliberately inserts a bipolar violation when excessive zeros
in the data stream are detected. The receiver recognizes
these special violations and decodes them as zeros. This
method enables the network to meet minimum pulse density
requirements. Use HDB3 unless AMI is required in your
application .
Alternate Mark Inversion (AMI): AMI coding does not inherently
account for ones density. To meet this requirement, the user
should ensure that the data inherently meets pulse density
requirements.
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SWITCH SET SUMMARY TABLE
Position
Function
Factory Default
Selected Option
SW1
Line Coding
Off
HDB3
SW3
Clock Mode
Off
SW4
Clock Mode
Off
Network
ON
OFF
