የምልክቶች ማውጫ፦ ከየት እንደሚጀመር

ቡድናችን በትርጉሙ ላይ እየሠራ ነው። ይህ ጽሑፍ ለጊዜው በአማርኛ አይገኝም፤ ስለዚህ በእንግሊዝኛ ቀርቧል።

You have a symptom, not a diagnosis. Find the row that matches what you see, run the first checks, and follow the link to the detailed material. Every row assumes the diagnostic ladder as the baseline: levels → clean → swap → OTDR.

Link state

Symptom	First checks	Likely causes	Read
Port down, module shows unsupported / invalid / Mod_Inv	host log, identity on the bench	vendor lock; identity or compliance codes the host rejects	Vendor lock, No link checklist
Port down, Rx −40 dBm / LOS on both ends	is Tx enabled? fibre continuity?	fibre cut, Tx disabled by host, Tx/Rx crossed, wrong BiDi pair, wrong wavelength for the mux	No link checklist, Physical mismatches
Port down, Rx and Tx levels fine	FEC and speed on both ends; AN on DAC	FEC mismatch, rate/breakout config, SGMII vs 1000BASE-X, CDR at wrong rate	Speed & rate, FEC & link training
Port down, Rx very high (> −3 dBm) on a short link	long-reach optic on a short span?	receiver overload	Physical mismatches
Works in one direction / LOS on one end only	compare Rx on both ends	dirty connector or weak laser on the failing side; polarity	DDM levels, Physical mismatches
Link flaps up/down	levels, CRC counters, connectors	contamination, marginal budget, thermal throttling	Link flapping
400G/800G module recognised but never ready, stuck LowPwr	CMIS module state, power class vs port	handshake / firmware / power class	CMIS issues, Power & thermal
DAC does not link, optic in the same port does	AN/link training, cable length, identity	AN disabled, unsupported cable, too long for the host	Copper & DAC, Speed & rate

Link up, but…

Symptom	First checks	Likely causes	Read
CRC / input errors climbing	Rx level vs baseline; FEC corrected counters; clean	dirt, marginal budget, dispersion at 10G+ on long CWDM	Link flapping, DDM levels
Slow throughput on a multi-lane link, no alarms	per-lane Rx/bias	one degraded lane hidden by LACP	Failures, Per-lane diagnostics
Works at 25G, dead at 10G (or 100G ok, 4×25G breakout not)	rate codes, CDR bypass, host breakout config	CDR range, module not breakout-capable, missing extended compliance code	Speed & rate, CDR
Absurd DDM values (0 °C, +10 dBm, 0.00 V)	byte 92 calibration bits	external calibration not applied, zeroed constants	Calibration
Tx power identical across a batch	compare modules	constant Tx written to memory	DDM levels
Module hot, port disables it, "power exceeds" log	power class byte vs port rating; airflow	class mismatch, thermal shutdown	Power & thermal
Everything fine for a year, then sudden failures	Tx bias trend, batch	laser ageing, bad batch, heat	Failures
Modules died after a switch firmware upgrade	host release notes; identity	stricter identity checks; clones failing authentication	Vendor lock, Failures

On the bench (programmer / CodingBox)

Symptom	First checks	Likely causes	Read
Module not detected on the programmer	seating, form-factor adapter, power-up time	not seated, wrong cradle, module in LowPwr	EEPROM read/write errors
Reads return FFh / 00h or garbage	address (A0h/A2h/page), bus speed	I²C NACK, wrong page, bus too fast	EEPROM read/write errors
WRITE FAIL	password, WP type, clock speed	protected module, hardware WP, timing	Write-protection types, EEPROM recoding
Write "succeeds" but reverts after power cycle	module type	temporary storage needs a save command	Write-protection types
Host rejects module after edit	checksums	stale CC_BASE / CC_EXT / CC_DMI	Memory map

Access networks

Symptom	First checks	Likely causes	Read
ONU does not register on the OLT	serial / LOID, PON standard, ONU Rx	whitelist, wrong wavelength plan (GPON vs XGS-PON), Rx out of class	PON problems
ONU shows LOS	SC/APC cleanliness, splitter, polish	dirt, UPC in an APC plant, fibre	PON problems

If nothing matches

Work the no-link checklist top to bottom, then read the module on the bench with CodingBox: the Check transceiver screen tells you what the module claims to be, and DDM what it is actually doing.

በዚህ ጽሑፍ ውስጥ ትክክል ያልሆነ መረጃ ወይም ስሕተት ካገኙ፣ የሚመለከተውን ክፍል ይምረጡና Ctrl+Enter በመጫን ።