3Com 3C13755-US - Router 5642 Installation Manual page 26

24 C 2: I
HAPTER NTRODUCING
8-Bit DIP Switch
Front Panel and LEDs
R 5012 SIC
OUTER S
Features of the 1-Port Fractional E1 SIC
Table 20
Feature
HDLC
Q.921, Q.931
The 1-Port Fractional E1 SIC is compatible with both 75-ohm impedance and
120-ohm impedance. The interface card matches different types of impedance
through an 8-bit DIP switch. By default, all eight positions of the DIP switch are on.
Table 21 lists the implications and configuration modes of the 1-Port Fractional E1
SIC internal 8 BIT DIP switch.
Table 21 Implications and Configuration Modes of the 1-Port Fractional E1 SIC Internal 8
BIT DIP Switch.
DIP Switch
1BIT
2BIT
3BIT
4BIT
5BIT
6BIT
7BIT
8BIT
Figure 23 illustrates the front panel of the 1-Port Fractional E1 SIC.
Figure 23 Front Panel of the 1-Port Fractional E1 SIC
Description
LAPB
75-ohm Impedance
Meaning Configuration Mode
Switch for ON
75-ohm/120-ohm
options
ON
ON
ON
ON
Switch for RxRing Off: RxRing grounding
grounding mode via capacitor
options
Switch for RxShield
grounding options
Switch for RxShield
grounding options
120-ohm Impedance
Configuration Mode
OFF
OFF
OFF
OFF
OFF
On: RxShield
grounding
Off: RxShield
unwinding
Off: RxShield
grounding via
capacitor
On: RxShield directly
grounding