System Limitations

The following list represents the most important limitations in the InterFAX system.
Other limitations may apply but will usually not have an impact on users, however please note that this list may change over time.

For all general support queries, please visit our help sections – here.

Outbound Service

  • Maximum number of pages per fax: 100 pages (more may be accommodated upon request).
  • Maximum number of email to fax recipients (total addresses in ‘To:’ and ‘Cc:’ lines.) per submission: 500 addresses.
  • Maximum number of recipients in a single submission (faxing via lists or submission via web service): 20,000 recipients.
  • Maximum total filesize of fax attachments: 20MB.
  • Maximum total filesize of fax attachments, where the email is electronically signed: 10MB.
  • Fax images are stored and visible for: 14 days.
  • For prepaid users: Fax information is kept for 30 days after the prepaid card that was used at the time has been depleted.
  • For invoiced users: Fax information is kept for 30 days after the end of the month during which the fax was sent.
  • Maximum postpone time: 14 days.
  • Unable to support password-protected files.
  • Unable to support read-only files (which bring up a pop-up when opened).
  • Macros are disabled. Do not use macros, as they may affect document output.
  • Supported attachment file types: Please see the support page – here, for a complete list of supported file types.
  • Charset ‘Windows-31J’ is currently not supported by Windows, as a result it is not supported by InterFAX. As an alternative, please use Charset ‘shift_jis’ instead. For more information, please see the article – here.
  • Maximum number of file attachments in Control Panel ‘Send Fax’: 5 attachments.
  • Maximum frequency of polling for fax status: Up to 6 requests per minute.

Inbound Service

  • An account manager may define up to 10 additional shared properties.
  • Maximum number of forwarding addresses: 25 addresses.
  • Maximum allowed time between page breaks: 600 seconds.
  • The user may download fax image/s in the following formats: PDF, TIF, PNG.
  • Users can store received messages and view them for 12 months. Extended storage period is available, please visit our pricing page for additional details.
  • Maximum frequency of polling for fax status: Up to 6 requests per minute.

SOAP Web Service

  • Maximum request size of any type: 8 MB.
  • Maximum file size when using partial upload: 20 MB.
  • Maximum frequency of polling for fax status: up to 6 requests per minute.
  • Maximum number of items returned in the following methods: (for outbound faxes) FaxStatus, FaxStatusEx, FaxQuery, FaxQuery2 and (for inbound faxes) GetList, GetList2: 100 items.
    However, when querying by verb Parent in the FaxQuery and FaxQuery2 methods (that is, when retrieving transactions in a broadcast): 20,000 items.
  • Maximum chunk size when using GetImageChunk download (of inbound faxes): 4 MB.

REST Web Service

  • Maximum request size of any type: 8 MB.
  • Maximum frequency of polling for fax status: up to 6 requests per minute.
  • Maximum number of items returned in the following methods: (for outbound faxes) Faxes, Completed and (for inbound faxes) GetList: 25 items.

Online Control Panel

  • Session timeout (time of inactivity before user is logged out): 15 minutes.
  • Response timeout: 90 seconds.
  • Maximum file size of fax image for downloading from the site: 4 MB
  • The online control panel is supported by the following web browsers: Google Chrome, Mozilla Firefox, Microsoft Edge and Internet Explorer 11.

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