User guide

Installation
DCM-1 User Manual v1.0 21
Connections
CDR-1s are connected to the DCM-1’s CDR-1 PORTS
using standard unscreened CAT-5 cable and RJ45 connectors.
It may be possible to use pre-made CAT-5 “patch cables”
to connect any CDR‑1s installed close to the DCM‑1;
otherwise CAT-5 cable and crimp RJ45 plugs should be used.
NOTE: All CAT‑5 cabling should be wired “pin‑to‑pin”;
“crossed” or “null” cables will not work.
Wire the RJ45 connectors as per the pinout diagram at
page 54.
Note that the single CAT-5 interconnection provides DC
power as well as data. A full pin allocation of the
CDR-1 ports can be found in the Appendix at the end of this
manual.
Any of the four CDR-1 PORTS may be used. Two of these
are labelled PORT A and the other two PORT B, but the
four are electrically identical. However, use of Port A/Port B
has relevance to how terminations are set (see below).
The CDR-1 is equipped with two RJ45 connectors, labelled
POWER IN and POWER OUT. The “rst” CDR‑1 in a
daisy-chain wiring system should be connected to the
DCM-1 using its POWER IN connector. The POWER OUT
connector on this CDR-1 should be connected to the
POWER IN of the next CDR-1 in the chain, and so on until
the last CDR-1 in the chain.
Network Terminations
The CAT-5 wiring connecting the DCM-1 and CDR-1s is
essentially a data network, and as such, must be correctly
terminated. Both the DCM-1 and CDR-1 are provided with
means of setting their network terminations ON or OFF.
The rule governing terminations is:
Devices (DCM-1 or CDR-1) at the ends of a cable run
must have their terminations set ON.
All intermediate devices must have their terminations
set OFF.
If both connectors on the same DCM-1 CDR-1 PORT
(either PORT A or PORT B) are being used, the
DCM-1 may be considered as an intermediate device,
and its termination should be set to OFF.
The correct termination setting is indicated for each device
in the three network examples illustrated above. Note that
in Network Diagram 1, the DCM-1’s Ports A and B are both
in use, but only one connector is used on each. The ports
are thus at the ends of the chains, and their terminations
must therefore be set ON. In Network Diagram 2, all four
ports are in use, so the DCM-1 is “mid-chain” with respect
to both ports, so both terminations should be set OFF.
There are two network terminations in the DCM-1, one for
each port. These are set by internal jumpers J6 (Port A) and
J13 (Port B). See page 51 for details of jumper locations.
The port termination is ON when the jumper is in place.
Remove the jumper (carefully, with a pair of long-nosed
pliers) to set the port termination OFF.
The CDR-1 network termination is set by jumper J2. This
has two possible positions, marked MID (termination OFF)
and END (termination ON).
•
•
•
J2 J1
MID
END
ON
OFF
J2 J1
MID
END
ON
OFF
Diagrams showing CDR-1 jumper settings for :
a) termination OFF (MID), b) termination ON (END).
Note Jumper J1 not shown.
J2 J1
MID
END
ON
OFF
POWER
OUT
POWER
IN
FROM
DCM-1
EXT POWER
RJ45 SOCKETS FOR
DATA
INTERCONNECTION
CO-AXIAL SOCKET
FOR EXTERNAL PSU
TO NEXT
CDR-1
Data and external power connections on the CDR-1