H3C Technologies H3C MSR 50 - Manual (Page 141)

3-37
DIP Description
Configuration of
75-ohm impedance
Configuration of
120-ohm impedance
7BIT
RxShield grounding
mode selection switch
—
ON: RxShield is
grounded.
OFF: RxShield is not
grounded.
8BIT
SxShield grounding
mode selection switch
—
OFF: RxShield is
grounded via capacitance
ON: RxShield is
grounded directly.
:
z
It is recommended to select the DIP switch of MIM-1E1/MIM-2E1/MIM-4E1 and
MIM-1E1-F/MIM-2E1-F/MIM-4E1-F modules in this way: when connecting 75-ohm cable, flip
BIT1-8 to ON, and when connecting 120-ohm cable, flip BIT1-8 to OFF. Positions of DIP switches
can only be changed by the trained personnel.
z
By default, all of the DIP switches of MIM-1E1/MIM-2E1/MIM-4E1 and
MIM-1E1-F/MIM-2E1-F/MIM-4E1-F modules are factory-configured to ON, that is, the impedance
of E1 interface is 75-ohm.
Connecting the interface cable
z
Read the mark identifying a port before you connect a cable to it, making sure it is the correct port.
Wrong connection tends to damage interface modules and even the Router;
z
Some protection measures are taken for MIM-1E1/MIM-2E1/MIM-4E1 and
MIM-1E1-F/MIM-2E1-F/MIM-4E1-F modules. Still, you are recommended to install a special
lightning arrester at the input end of the cable leading to the outdoors in order to protect the line
against lightning strikes more efficiently.
Connecting interface cable of MIM-1E1/MIM-2E1 and MIM-1E1-F/MIM-2E1-F/MIM-4E1-F
modules
Step1 Check the type of E1 cable, and set the DIP switches of MIM-1E1/MIM-2E1 or MIM-1E1-F/MIM-2E1-F
module correctly;
Step2 Plug the DB-15 connector of the E1 cable into the E1/FE1 port on the module;
Step3 Connect the other end of the E1 cable to the network device;
1) When using 75-ohm unbalanced coaxial cable,
z
Connect its BNC connector to the device to be connected directly, if cable extension is not needed;
z
Connect its BNC connector to a coaxial connector and the other end of the coaxial connector to the
device to be connected through a 75-ohm E1 trunk cable, if cable extension is needed;