Fax Failure Reasons

When a fax fails, either for an outbound fax or an inbound one, the failure is captured on the Communication (opens in a new tab) resource.

Communication Resource Shape on Failure

A failed fax has:

Communication.status = "stopped"
Communication.statusReason populated with a code and human-readable description

statusReason always uses the same coding system:

{
  "statusReason": {
    "coding": [
      {
        "system": "https://terminology.fhir.oystehr.com/CodeSystem/fax-failure-reason",
        "code": "<code representing the failure reason>",
        "display": "<human-readable description of the failure reason>"
      }
    ],
    "text": "<human-readable description of the failure reason>"
  }
}

Outbound Fax Failure Codes

Codes synthesized by the fax service call-progress callbacks for outbound faxes:

Code	Meaning
`BUSY`	The recipient line was busy.
`NO_ANSWER`	The recipient did not answer the call.
`FAILED`	The call failed for an unspecified reason.
SIP result code (e.g. `486`) or `FAILED`	When a SIP result code is received on a failed call, that numeric code is recorded here.
`UNKNOWN`	The fax service received a `failed` status callback but no code or message was provided.

Common Fax Transmission Errors

These errors can occur on either inbound or outbound faxes. The fax service stores the error code in statusReason.coding[0].code and the error message in statusReason.text.

Error Message	Description
Connection Failed	There was no receiver on the other end of the call to connect to. The receiver is likely not a fax machine.
Document generation error	There was an error while generating the document. This could be due to the file being deleted before sending.
Failed to train with any of the compatible modems	A remote fax machine was detected, but the sending and receiving modems could not establish communication.
Fax transmission not established	Could not detect a remote fax machine. This could be due to there being no fax machine on the receiving end or a connectivity, carrier, or incompatibility issue.
Log entry lost	The call started but the log entry for the call was lost or incomplete. This is rare and indicative of a system or network issue.
No response after sending a page	The remote fax machine did not acknowledge that it received a page of the fax. It may still have printed the page and preceding pages.
Received no response to DCS or TCF	The bulk fax service could not successfully determine the remote machine's fax capabilities. Check whether the recipient fax machine supports T.38/T.30 fax protocols.
The call dropped prematurely	The call dropped due to a non-fax transmission error. The receiver likely hung up or is a voice number.
The HDLC carrier did not stop in a timely manner	A fax transmission was initiated with the receiver, but there was a synchronization (timing) error.
Timed out waiting for initial communication	A call was established with the receiver, and the fax service attempted to establish a fax session, but there was no fax response. Another case of the recipient probably not being a fax machine.
Unexpected DCN while waiting for DCS or DIS	The fax machine received a disconnect (DCN) signal unexpectedly during the initial negotiation phase. Check whether the recipient fax machine supports T.38/T.30 fax protocols.
Disconnected after permitted retries	The fax service attempted to send the same message multiple times unsuccessfully.
Far end cannot receive at the resolution of the image	The remote fax machine does not support receiving faxes sent at the requested resolution. Try again after lowering quality.
Received a DCN from remote after sending a page	The remote fax machine responded with a disconnect (DCN) message after a page was sent. It may still have printed the page and preceding pages.
Unexpected message received	The fax service received a message it did not expect given the current context.
Unexpected DCM after EOM or MPS sequence	The remote fax machine disconnected unexpectedly after receiving a page of a multi-page fax. It may still have printed the page and preceding pages.
Document loading error	The fax service attempted to generate the message to send, but a document was missing.
Invalid ECM response received from receiver	The receiving fax machine's error-correction response did not match expected parameters. Check whether the recipient fax machine supports T.38/T.30 fax protocols.

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The Fax Service does not yet support FHIR R5 (opens in a new tab).

Receiving a Fax FHIR