Appendix C Setting The Fixed E1 Port Impedance - HP MSR20-1X Series Installation Manual

Appendix C Setting the fixed E1 port
impedance
CAUTION:
The DIP switches are located at the mother board inside the router chassis. To operate the DIP switches,
you must open the router chassis. For more information, see the chapter "Installing and upgrading internal
modules."
By default, the impedance of the fixed E1 port on MSR20- 1 2/20- 1 2-W is 75 ohms. By using the internal
DIP switches, you can change the interface impedance from 75 ohms to 120 ohms.
Figure 52 Default setting of DIP switches
1
2
3
4
5
6
7
8
Table 1 DIP switch setting description
DIP
1BIT
2BIT
3BIT
4BIT
5BIT
6BIT
on
Description
75-ohm/120-ohm
selection switch
RxRing grounding mode
selection switch
Configuration of
75-ohm impedance
ON
ON
ON
ON
ON
OFF: RxRing is grounded
via capacitance.
ON: RxRing is grounded
directly.
49
Configuration of
120-ohm impedance
OFF
OFF
OFF
OFF
OFF
N/A