Fanuc alarm 447: HSSB COMMUNICATION ERROR (CH2)
30i/31i/32i system alarm · Fanuc 30i/31i/32i-B
What it means
Communication over HSSB channel 2 (the high-speed serial bus linking the CNC to a PC or another unit) failed. Fanuc lists power-supply problems, external noise, connector contact failure, cable breakage or failure of the HSSB interface on either side as causes. Replace both sides' HSSB boards; if that fails, replace the CH2 HSSB cable.
Likely causes
- HSSB cable disconnected or damaged
- Interface board fault on CNC side or PC side
- Power supply abnormality or noise affecting one end of the link
Triage note: Alarm 448 is the identical fault on channel 1.
Replacement parts
We supply the following units for this alarm — tested, warranty-backed:
- Request a quote →
HSSB interface board (both ends suspected)
board · Common cause
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HSSB cable CH2 (if board swap does not clear)
cable · Common cause
Need the part urgently?
Send us alarm 447 with your machine details — typical RFQ turnaround is 24–48h.