2.
Gently
twist the screw driver to pop the case open as shown in
Figure 2, below. Be careful not to damage the case or
connector as you twist the screw driver.
3.
Once you have opened the case of the Model 2020/2020N,
you will see the green DCE/DTE strap located on the PC
board in the position shown in Figure 3, below. The DCE/DTE
strap is oriented closest to the RS-232 interface.
4. The arrows on top of the strap indicate the orientation of the
Model 2020's ports. For example, if the "DCE" arrow is
pointing toward the DB-25 connector, then the Model
2020/2020N's strap is set so that it sees its DB-25 port as
DCE. It wants to plug into the DB-25 port of a terminal or
other DTE. The arrow pointing toward the cable at the rear of
the PC board shows the orientation of the Model 2020's V.35
port.
5.
To reverse the DCE/DTE orientation, pull the entire green
strap out of its socket and rotate it 180 degrees. Then plug it
back into the socket. You will see that the arrows on top now
point in the opposite directions, showing the new DCE/DTE
orientation of the Model 2020.
6.
When you're done, realign the case halves (don't forget the
captive screws and saddle washers) and snap them back
together.
5
6
Figure 2. Popping open the case
DCE
DTE
DCE/DTE
Strap
Figure 3. DCE/DTE strap orientation on PC board
RS-232
Interface
RS-232
Interface