3com MSR 20 User Manual
30
C
HAPTER
2: S
MART
I
NTERFACE
C
ARDS
c
CAUTION:
■
When setting internal DIP switch, you are recommended to: turn ON all BITs
from 1 to 8 when a 75-ohm cable is connected. Turn OFF all BITs from 1 to 8
when a 120-ohm cable is connected;
from 1 to 8 when a 75-ohm cable is connected. Turn OFF all BITs from 1 to 8
when a 120-ohm cable is connected;
■
The default configuration of internal DIP switch is that all the 8 positions of the
BIT switch are ON, that is, the E1 interface impedance is 75-ohm.
BIT switch are ON, that is, the E1 interface impedance is 75-ohm.
Interface LEDs
SIC-1EPRI panel is shown in the following figure:
Figure 19 SIC-1EPRI panel
SIC-1E1-F panel is shown in the following figure:
Figure 20 SIC-1E1-F panel
The status description of the LEDs is given in the following table:
7BIT
Switch for RxShield
grounding options
grounding options
- ON:
RxShield
grounding
OFF: RxShield
ungrounding
ungrounding
8BIT
Switch for RxShield
grounding options
grounding options
- OFF:
RxShield
grounding via
capacitor
capacitor
ON: RxShield
directly grounding
directly grounding
Table 6 Description and settings of the internal DIP switch of SIC-ERRI/SIC-1E1-F
DIP switch
Description 75-ohm
impedance
120-ohm
impedance
impedance
Table 7 Description of the LEDs on SIC-1EPRI/SIC-1E1-F panel
LED Description
LINK
ON means carrier signal has been received.
OFF means no carrier signal has been
received.
received.
ACT
OFF means no data is being transmitted or
received; blinking means data is being
received or/and transmitted.
received; blinking means data is being
received or/and transmitted.
Fractional E1