NEC UPD98413 User Manual page 78

(4) Transmitting Line RDI (Line Remote Defect Indication)
Line RDI is a signal that reports detection of a line receive failure (LOS, LOF, or Line AIS) to a unit in the
upstream.
• • • • Transmitting/Terminating method
The Line RDI frame can be transmitted in the following three ways. The frame is transmitted or cleared by
observing the boundary of the frame.
<1> Automatic return transmission
The Line RDI frame is automatically transmitted if any of the events of LOS, LOF, and Line AIS is
detected at the reception side. When the µ PD98413 has recovered from the event, it resumes
transmitting the ordinary frame, but µ PD98413 guarantees to generate the Line RDI frame for at least 20
frames. This function is enabled in the default mode, but can be disabled by using the ALRDIM bit of the
MDLOHT register.
<2> Set the LRDI bit of the CMALM register to 1. While this bit is set to 1, the Line RDI frame is transmitted.
<3> Drive the TALM pins to the Line RDI code. While these pins are set to the Line RDI code, the Line RDI
frame is transmitted.
• • • • Line RDI frame
This frame has "110" in bits 6 to 8 of the K2 byte of the OH byte.
(5) Transmitting Path RDI (Path Remote defect Indication)
Path RDI is a signal that reports detection of a path receive failure to a unit in the upstream. µ PD98413 supports
two modes of One-bit RDI and Enhanced RDI. This mode can be selected by the PRDIM bit of the MDPOHT
register.
One-bit Path RDI
• • • • Transmitting/Terminating method
The One-bit Path RDI frame can be transmitted in the following three ways. The frame is transmitted or
cleared by observing the boundary of the frame.
<1> Automatic return transmission
The One-bit Path RDI frame is automatically transmitted if any of the events of LOS, LOF, Line AIS, LOP,
Path AIS, and (LCD) is detected at the reception side.
When the µ PD98413 has recovered from the event, it resumes transmission have the ordinary frame
(Bit5 of G1 byte is "0"), but µ PD98413 guarantees to generate the One-bit Path RDI frame for at least 20
frames. This function is enabled in the default mode, but can be disabled by using the APRDIM bit of
the MDPOHT register. LCD is not included in the condition of automatic transmission of the One-bit
Path RDI in the default mode, but can be included in the condition by using the LCDO bit of the
MDPOHT register.
<2> Set the PRDI field of the CMALM register to 001. While this field is set to 001, the One-bit Path RDI
frame is transmitted.
<3> Drive the TALM pins to the One-bit Path RDI code. While these pins are set to the One-bit Path RDI
code, the One-bit Path RDI frame is transmitted.
• • • • One-bit Path RDI frame
This frame has "1" in bit 5 of the G1 byte of the OH byte.
78
CHAPTER 3 FUNCTIONAL OUTLINE
PRELIMINARY
NEC confidential and Proprietary