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Fax error codes tell you which step of the call failed: dialing, the handshake, or the page transfer. On HP machines, codes in the 200s usually mean a communication failure, codes like 344 or 350 point to error-correction problems, and busy or no-answer conditions get their own codes. Most are line-quality problems, not broken machines, and a retry often fixes them.
| Code | Meaning | What to do first |
|---|---|---|
| 232 | Communication failure between the two machines; the remote side may have pressed Stop or lost power mid-call | Retry; if it persists, try at a different time of day |
| 344 to 349 | The remote machine stopped responding, often line noise or an interrupted connection | Retry; disable call waiting, which can click the line mid-fax |
| 350 to 353 (ECM) | Error Correction Mode failure: too many corrupted data blocks to repair | Turn ECM off and resend; pages may arrive with minor flaws but will go through |
| Busy / no answer | The number rang busy or no fax machine picked up; a dialing problem, not a transfer problem | Confirm the number is a fax line, then retry; see the busy-signal guide for the full checklist |
Codes vary by manufacturer, so a Brother or Canon machine won't show these same numbers, but the categories are universal: dial failures, handshake failures, and transfer failures. The code on your report tells you which of the three broke, which is genuinely useful, because each has a different fix.
Error Correction Mode is the fax protocol's quality control. With ECM on, the sending machine breaks the page into blocks, the receiving machine checks each block, and corrupted blocks get retransmitted until they're clean. On a noisy line, that retransmission loop can spiral until the call fails with a 350-series code. Turning ECM off skips the retransmission: corrupted blocks print as smudges or streaks instead of killing the whole fax. So disabling ECM is a real fix, not a superstition, and it's the first thing support technicians suggest for repeated failures. The trade-off is that a page that would have failed cleanly may now arrive with a blurred line or two, which is acceptable for text and questionable for signatures or fine print.
Resend first if the code points at the line: 232, 344, or an ECM error, especially if it worked yesterday. Phone-line conditions change hour to hour, and the same fax often sails through on the second try. Call the recipient when the failure repeats three times, the code suggests the remote end hung up (someone may be manually answering a shared voice-fax line), or you suspect you have the wrong number entirely. A quick call also resolves the case where their machine is out of paper or toner, which produces receive-side failures no amount of resending will fix. And if you're faxing over an internet phone line, the codes may keep coming no matter what you try; that's a VoIP problem, not a dialing problem.
Mostly, yes. Online fax services transmit from commercial phone lines with clean signaling, so the line-noise failures behind the 300-series codes rarely happen. Your pages go out as a digital file, and the service handles redials automatically. LetterAgent works this way: describe the document to your AI assistant, approve the exact quoted price, and the fax is sent to US and Canadian fax numbers. Fax is currently in testing, so check with your assistant about availability before you count on it.
Ready to fax it? Fax with LetterAgent: describe it to your AI assistant, approve the exact quoted price, and it is sent.
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