DIP Switches on the GEIUA/GEIUB/GEIUP/GEIUT(EIUa)

The physical boards of the GEIUA, GEIUB, GEIUP, and GEIUT are the same. After being loaded with different software, the physical boards perform different functions. They have the same types of DIP switches: S1, S3, S4, S5, and S6.

Figure 1 shows the layout of the DIP switches on the GEIUA/GEIUB/GEIUP/GEIUT.

Figure 1 Layout of the DIP switches on the GEIUA/GEIUB/GEIUP/GEIUT

(1) Sub-board

(2) Bottom plate

CAUTION:

All the DIP switches are located on the front side of the sub-board. The front of the sub-board faces and fits into the bottom plate. Therefore, you should remove the sub-board before setting the DIP switches.

Table 1 describes the DIP switches on the GEIUA/GEIUB/GEIUP/GEIUT.

**Table 1** DIP switches on the GEIUA/GEIUB/GEIUP/GEIUT
DIP Switch	DIP Bit	Description	Setting for 75-ohm Coaxial Cable	Value of DIP Bit for 75-ohm Coaxial Cable	Setting for 120-ohm Twisted Pair Cable	Value of DIP Bit for 120-ohm Twisted Pair Cable
S1	8	Used to select the impedance on E1/T1 links 0-7	ON	0	OFF	1
	7	Used to select the impedance on E1/T1 links 8-15	ON	0	OFF	1
	6	Used to select the impedance on E1/T1 links 16-23	ON	0	OFF	1
	5	Used to select the impedance on E1/T1 links 24-31	ON	0	OFF	1
	1-4	Reserved
S3	1-8	Used to set the protection grounding of the transmitting end of E1/T1 links 0-7	ON	0	OFF	1
S4	1-8	Used to set the protection grounding of the transmitting end of E1/T1 links 8-15	ON	0	OFF	1
S5	1-8	Used to set the protection grounding of the transmitting end of E1/T1 links 16-23	ON	0	OFF	1
S6	1-8	Used to set the protection grounding of the transmitting end of E1/T1 links 24-31	ON	0	OFF	1

Table 2 describes different switches listed in Table 1.

**Table 2** Switch types related to the DIP bits
DIP Switch	Description
E1/T1 impedance selection switch	Used to select the logical transmission mode of the board and to notify the software of the current transmission mode
Switch used to set the protection grounding of the E1/T1 transmitting end	Used to control the grounding of the transmitting end of the E1/T1 signals: When E1/T1 signals are transmitted through a 75-ohm coaxial cable in unbalanced transmission mode, set the DIP bit to ON and ground the TX end. When E1/T1 signals are transmitted through a 120-ohm coaxial cable in balanced transmission mode, set the DIP bit to OFF and ground the TX end.

NOTE:

By default, the DIP switches are set in 75-ohm coaxial transmission mode.
The setting for the DIP switches on the active EIUa board must be the same as that for the DIP switches on the standby EIUa board.
The receiving ends should not be grounded in either balanced or unbalanced modes.
Pay attention to the mapping between the two types of DIP switches.