12
HIGH-SPEED 2-WIRE SHORT-RANGE DSL LINE DRIVER RACK CARD
3.1.2 C
ONNECTING TO A
DTE D
EVICE
The serial port on most interface modules (all except the X.21 module) is hard-
wired as a DCE. Therefore these modules “want” to plug into a DTE such as a
terminal, PC, or host. When making the connection to your DTE device, use a
straight-through cable of the shortest possible length—we recommend 6 feet
(1.8 m) or less. When purchasing or constructing an interface cable, please refer to
the pin diagrams in
Appendix A
as a guide.
3.1.3 C
ONNECTING TO A
DCE D
EVICE
If the mDSL Rack Card interface module is hard-wired as a DCE (all except the
X.21 module), you must use a null-modem cable when connecting to a modem,
multiplexor, or other DCE device. This cable should be of the shortest possible
length—we recommend 6 feet (1.8 m) or less. When purchasing or constructing a
null-modem interface cable, use the pin diagrams in
Appendix A
as a guide.
NOTE
Pinout requirements for null-modem applications vary widely between
manufacturers. If you have any questions about a specific application,
call Black Box Technical Support at 724-746-5500.
3.1.4 C
ONFIGURING THE
X.21 I
NTERFACE
M
ODULE
The serial port on the X.21 interface module is default wired as a DCE, but may be
switched to a DTE. This is done by reversing the orientation of the DCE/DTE
strap, as described below:
To reverse DCE/DTE orientation, remove the interface module according to the
instructions in
Section 3.1.1
. The DCE/DTE strap is located on the top side of the
interface module’s PC board. The arrows on the top of the strap indicate the
configuration of the X.21 port (for example, if the DCE arrows are pointing
toward the rear card connector, the X.21 port is wired as a DCE). Reverse the
DCE/DTE orientation by pulling the strap out of its socket, rotating it 180º, then
plugging the strap back into the socket. You will see that the DCE/DTE arrows now
point in the opposite directions, showing the new configuration of the X.21 port.
Reinstall the module according to the instructions in
Section 3.1.1
.
3.1.5 C
ONFIGURING
DIP-S
WITCH
S
ET
S1
Switch S1 is used to set the address of the card in the SNMP Management Module.
When the mDSL Rack Card is installed with a SNMP Management Module, the
cards and their remote units can be SNMP managed using a standard Network
Management Station (NMS) or a standard Web browser (Netscape
®
Navigator or
Internet Explorer
®
). For more information about setting the address, refer to the
SNMP Management Module Users’ Manual
(part number RM261C-SNMP).
