84CHAPTER 3: MULTIFUNCTIONAL INTERFACE MODULES

For the pinouts of E1 cables, see Low-End and Mid-Range Series Routers Cable

Manual.

c CAUTION: 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.

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.

Figure 94 120-ohm 4E1 conversion cable

DB25¹

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DB15Ä

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3Com MSR 30, MSR 20, MSR 50 manual Conversion cable for MIM-4E1/MIM-4E1-F module, ohm 4E1 conversion cable