H3C Technologies H3C MSR 50 User Manual
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Figure 3-38 E1 120-ohm balanced twisted pair cable
You can select a network interface connectors with an RJ-45 receptacle at both ends that connect two
120-ohm balanced twisted pair cables with BNC connectors. The network interface connector is used in
the extension connection with E1 120-ohm balanced twisted pair cables.
In addition, a 75-ohm to 120-ohm adapter is provided.
For the pinouts of E1 cables, see Low-End and Mid-Range Series Routers Cable Manual.
E1 cable, coaxial connector, network interface connector and 75-ohm to 120-ohm adapter are all
optional accessories. Please order them when purchasing MIM-1E1/MIM-2E1 or
MIM-1E1-F/MIM-2E1-F modules. By default, they are not provided.
2) Conversion cable for MIM-4E1/MIM-4E1-F module
MIM-4E1/MIM-4E1-F modules provide two types of “1-to-4” conversion cables: 120-ohm 4E1
conversion cable and 75-ohm 4E1 conversion cable. At one end of these two types of cables is a DB-25
connector used to connect a router, and at the other end are four DB-15 connectors used to connect E1
cables. You can distinguish these two types of cables by the main labels. There are the words
“MIM-4E1-120ohm-CAB “printed on the main label for 120-ohm 4E1 conversion cables whereas the
words “MIM-4E1-75ohm-CAB” are printed on the main label for 75-ohm 4E1 conversion cables.
The two types of cables have a similar appearance, as illustrated in the following figures. However, a
75-ohm 4E1 conversion cable uses 8-core coaxial cables but a 120-ohm 4E1 conversion cable uses
four twisted pair cables.