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CHAPTER 6 PHY FUNCTION
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(d) Transmitting Path RDI (FERF) (Path Remote Detect Indication/Far End Receive Failure)
This signal reports, to units upstream, that a path receive failure (LOS, LOF, Line AIS, LOP, LCD, Path
AIS) has been detected. The
μ
PD98405 sets the fifth bit of the overhead G1 byte of the transmit frame
to "1" for transmission if the PRDI bit of command register 1 (PCMR1) is set to 1. If an internal cause
(occurrence of LOS, LOF, Line AIS, LOP, LCD, Path AIS) is detected, it is automatically transmitted.
This automatic transmission upon the occurrence of an internal cause can be masked by the IACM
register.
Transmit overhead:
G1 byte (5th bit) = 1
Transmission/cancellation condition:
Setting by the command register
Automatic transmission/cancellation upon the occurrence of
the following internal causes (can be masked)
Detection/cancellation of LOF
Detection/cancellation of LOS
Detection/cancellation of LOP
Detection/cancellation of LCD
Detection/cancellation of Line AIS
Detection/cancellation of Path AIS
(2) Monitoring circuit quality (performance monitor)
(a) Bit Interleaved Parity (BIP)
B1 byte (Section BIP-8):
BIP-8 calculation is performed for all frame data (scrambled data) except the first line of the SOH
(section overhead) of the transmit frame, BIP8 calculation is performed on a specific area, and the
result of the calculation is inserted into the B1 byte of the next transmit frame for transmission.
B2 byte (Line BIP-24):
BIP-24 calculation is performed for all frame data (data after descrambling) except the first,
second, and third lines of the SOH of the previous frame, and the result of the calculation is
inserted into the B2 byte of the next transmit frame for transmission.
B3 byte (Path BIP-8):
BIP-8 calculation is performed for all payload data (data after descrambling) of the transmit frame,
and the result of the calculation is inserted into the B3 byte of the POH (path overhead) of the next
transmit frame for transmission.