Intel LXD381 manual Receive Polarity Selection, Output Enable Selection, Unused Switches

LXD381 — Evaluation Board for Octal E1 Applications

2.5Receive Polarity Selection

The polarity of RPOS/RNEG is determined by the CLKE switch in switch block S2. When the CLKE switch is OFF, RPOS/RNEG are active Low. When set to the ON position, RPOS/RNEG are active High. Note that the CLKE switch controls the LXT381’s RPOL pin.

2.6Output Enable Selection

The OE switch in switch block S3 controls the operation of the LXT381 output drivers. For normal operation (driver outputs enabled), set the OE switch to the ON position. Setting the OE switch to OFF forces the output drivers to the high impedance state.

2.7Unused Switches

Switches 3 and 4, in switch block S2, have no function on the LXD381 and should be set to the OFF position. Figure 2 shows the factory default settings for switch block S2.

Figure 2. S2 Factory Switch Settings

S2

FFO 1

2

3

4

CLKE

OE

NOTE: OFF position = Low

2.8Back-End Interface Connection

Eight 10 pin connectors (JP1 - JP8) provide access to the LXT381 digital signals to allow interfacing the back-end Framer/Mapper or ASIC with an external pattern generator. Figure 3 shows a typical connector (JP1 for channel 0) with the factory installed jumper connecting RCLK to TCLK. This jumper is normally installed when feeding analog test data from the line interface (TIP and RING).

8 Developer Manual