CX950 Hardware Reference Manual
7-4
3021M100-002
E&M 2-wire
and 4-wire
The E&M 2-wire and E&M 4-wire LIDs feature 600 Ohm line impedance.
Unlike the E&M 4-wire LID, the E&M 2-wire LID does not require the T1 to T1
or R1 to R1 connections in straight-through signalling or the T1 to T or R1 to R in
reverse signalling.
E&M 2/4-wire
The E&M 2/4-wire driver can accommodate both types of analog interface (2- o
4-wire) and several line impedances. Configuration is achieved through jumpe
settings on the LID.
Table 7-1 and Table 7-2 list the jumper settings for configuring the line impedance
and analog interface, respectively.
NOTE:
Default settings are 600-Ohm line impedance and 4-wire analog interface.
Table 7-1 Jumper Settings for E&M 2/4-wire Line Impedance
Line Impedance Jumper Required
LK2 LK1
600 Ohms resistive Yes Yes
900 Ohms resistive Yes No
ATT Complex: 900 Ohms in series with 2.16µF No Yes
Australian Complex: 220 Ohms in series with (820 Ohms//120nF) No No
Table 7-2 Jumper Settings for E&M 2/4-wire Analog Interface
Analog Interface LK3 Jumper Required
4-wire Yes
2-wire No