will change. The summary table below describes DIP switch S1
settings, including factory defaults.
3.1.2 SETTING THE DCE/DTE STRAP
The RS-232/V.35 interface on the Model 2065/66RC is DCE/DTE
switchable. The default setting is “RS-232/V.35 DCE to X.21 DTE”,
based upon how the converter sees its
own orientation. When
5
S1 SUMMARY TABLE
Position
RS-232/V.35 = DCE
RS-232/V.35 = DTE
ON = “CD from the RS-232/V.35
DCE must be ON in order for the
X.21 CONTROL signal
to turn ON”
OFF = “CD from the RS-232/V.35
DCE has no effect on the
CONTROL signal going to
the X.21 DCE”
ON = “CTS from the RS-232/V.35
DCE must be ON in order for the
X.21 CONTROL signal
to turn ON”
OFF = “CTS from the RS-
232/V.35 DCE has no effect on
the CONTROL signal going to
the X.21 DCE”
ON = “DSR from the RS-232/V.35
DCE must be ON in order for the
X.21 CONTROL signal
to turn ON”
OFF = “DSR from the RS-
232/V.35 DCE has no effect on
the CONTROL signal going to
the X.21 DCE”
ON = “INDICATION from the
X.21 DCE controls RTS and DTR
going to the RS-232/V.35 DCE”
OFF = “INDICATION from the
X.21 DCE controls RTS only
going to the RS-232/V.35 DCE.
DTR is always ON”
ON = “DTR from the RS-
232/V.35 DTE must be ON in
order for the X.21 CONTROL
signal to turn ON”
OFF = “DTR from the RS-
232/V.35 DTE has no effect on
the CONTROL signal going to
the X.21 DCE”
ON = “RTS from the RS-232/V.35
DTE must be ON in order for the
X.21 CONTROL signal
to turn ON”
OFF = “RTS from the RS-
232/V.35 DTE has no effect on
the CONTROL signal going to
the X.21 DCE”
(not applicable)
Set to OFF
(not applicable)
Set to ON
S1-1
S1-2
S1-3
S1-4
Note: Bold indicates factory default setting
configured this way, the Model 2065/66RC will want to connect to an
RS-232/V.35 DTE device. Changing the DCE/DTE strap orientation will
enable the Model 2065/66RC to connect to an RS-232/V.35 DCE
device. (Note: the X.21 port on the Model 2065/66RC is
always wired
as a DTE and is
not switchable. This port always wants to connect to
an X.21 DCE device.)
The RS-232/V.35 DCE/DTE strap is located near the rear of the
Model 2065/66RC front card’s PC board (see Figure 3, below). The
arrows on the top of the strap indicate the configuration of the Model
2065/66RC. For example, if the “DCE” arrows are pointing toward the
edge of the card (up), then the Model 2065/66RC is wired as a DCE
and wants to connect to an RS-232/V.35 DTE device.
To change the DCE/DTE orientation of the Model 2065/66RC’s RS-
232/V.35 interface, simply remove the strap and rotate it 180
0
, so that
the appropriate arrows are pointing toward the edge of the card.
6
Figure 3. Model 2065/66RC front card, with close-up of DCE/DTE strap.
DCE
➞
➞
DTE
➞
➞
