Black Box May-95 Cable Box User Manual


 
26
MULTI-FUNCTION LD CARD
The Multi-Function LD Card is wired as a DCE (Data Communications
Equipment) device. Therefore, it would normally be connected to a DTE
(Data Terminal Equipment) RS-232 device. You might need to run a special
cable or use a special adapter if the serial port of the RS-232 device you want
to attach is not the same type of connector as the one on your Card. Even if
the serial ports on the Card and the DTE are both RJ-45 connectors, you
might still need to use a specially pinned cable. Call your supplier for
technical support with these issues, or if you want to attach a DCE device to
the Card.
4.5 The Modem-to-Modem Line Cables and Connectors
The Multi-Function LD Card’s line port is always the upper port on its
interface module. It is a 6-pin RJ-11 connector on the -RJ11 models or an
8-pin RJ-45 connector on the -RJ45 models, pinned for a standard telco-wiring
environment, as shown in Table 4-3 and Figure 4-2 on the next page.
The Multi-Function LD Card operates half-duplex over two wires (one
twisted pair) or full- or half-duplex over four wires (two twisted pairs). In all
applications, the twisted-pair wire must be 26 AWG or thicker, unconditioned,
dry, and metallic. Both shielded and unshielded cable yield favorable results.
NOTE
The Multi-Function LD Card can only communicate in a closed data
circuit with another Multi-Function LD Card. It will not work with dialup
analog circuits, such as those used with standard modems. For further
information about acceptable wire grades, refer to the recommendations
in the Appendix.
The modem-to-modem cable connection must be specially cross-pinned, as
shown in Table 4-3 and Figure 4-2 on the next page. If your cabling includes
punchdown blocks, you can easily do the cross-pinning at a punchdown block.
If you will be running cable directly between two Multi-Function LD Cards,
you can get a custom cable from your supplier as a special quote, or you can
use regular straight-through-pinned cable and repin one of the RJ connectors
(that is, rearrange the wiring connections between the terminal block and the
actual contacts). You might need special crimping tools or new connectors;
call your supplier for these items, or for technical support if you have
difficulty.