3Com MSR 50, MSR 30, MSR 20 manual Setting DIP switches on the FIC-E1/FIC-E1-F cards, Configuration

FIC-1E1/FIC-2E1/FIC-4E1 and FIC-1E1-F/FIC-2E1-F/FIC-4E1-F 167

Figure 204 Default setting of the DIP switches for the FIC-E1/FIC-E1-F cards

on

1

2

3

4

5

6

7

8

The following table describes how to set a DIP switch on the FIC-E1/FIC-E1-F cards:

Table 115 Setting DIP switches on the FIC-E1/FIC-E1-F cards

			Configuration of
		Configuration of	120-ohm
DIP switch	Description	75-ohm impedance	impedance
1BIT	75-ohm/120-ohm	ON	OFF
	toggle switch
2BIT		ON	OFF
3BIT		ON	OFF
4BIT		ON	OFF
5BIT		ON	OFF
6BIT	RxRing grounding	OFF: RxRing is	-
	mode switch	grounded using
		capacitance.
		ON: RxRing is
		grounded directly.
7BIT	RxShield grounding	-	ON: RxShield is
	switch		grounded.
			OFF: RxShield is not
			grounded.
8BIT	RxShield grounding	-	OFF: RxShield is
	mode switch		grounded using
			capacitance
			ON: RxShield is
			grounded directly.

c CAUTION: When connecting an FIC-E1/FIC-E1-F card to an external 75-ohm cable, you are recommended to place BITs 1 through 8 to the ON position; when connecting the card to an external 120-ohm cable, place BITs 1 through 8 to the OFF position. Only trained personnel are allowed to change the settings of the DIP switches.

By default, all the DIP switch BITs are in the ON position (factory default), which means the impedance of E1 ports is 75-ohm.