How does inbound fax routing work?

An important ability for Network fax packages is to be able to determine the right recipient of an incoming fax.  GFI FaxMaker supports several ways of achieving this.  Each method has its advantages and disadvantages. Overall, DID routing is preferred for larger installations, and MSN and Line routing for smaller installations.  In this paragraph we discuss all the routing methods, their advantages and their requirements.

DID routing (ISDN or analog DID trunk)

Using either an ISDN line or a DID trunk, users can be assigned personal fax numbers without having to install physical fax lines for each number.  The number of the line is passed to GFI FaxMaker upon receiving the fax, and therefore GFI FaxMaker can route the fax to the correct user.
ISDN/DID (Direct Inward Dial) routing is generally considered the most reliable form of automatic inbound routing.  DID requires you to purchase virtual phone numbers from your telecom company, which you can assign to users or departments.  The virtual phone number (DID number) will be passed to GFI FaxMaker so that GFI FaxMaker knows to whom the fax should be routed.  The system is completely transparent to the caller and does not require any effort on his/her part.
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For routing based on ISDN DID
  • An ISDN Line with MSN/DID numbers
  • A capable fax card such as a Dialogic Brooktrout TR1034 Digital board
For routing based on analog DID
  • A DID line with X amount of numbers
  • A capable fax card (ex: Dialogic Brooktrout TR1034 Analog DID fax card)
Recommended environment:  Any environment where 100% reliability is required for inbound fax routing.  Example: Legal & Accounting offices

MSN routing (ISDN only)

This method is similar to DID routing.  It's only supported if using ISDN.  If using MSN routing, you do not need to purchase DID numbers.  Each ISDN line has 1 or more MSN numbers (usually 9) assigned to it.  For an ISDN card to answer a line, you need to specify which MSN numbers it should pick up the line for.  If your ISDN line has 9 MSN numbers, you can have 9 different routes for a fax.

Recommended environment:  Any environment where 100% reliability is required for inbound fax routing.  Example: Legal & Accounting offices

OCR routing

This method routes a fax to the correct user by recognizing the text on the fax (OCR), and finding keywords related to a recipient (for example, a first name, last name or job function).  If GFI FaxMaker cannot match a recipient, it will route the fax to the default recipient/router.
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  • The OCR fax module
  • Faxes that need to be routed should be typewritten
Recommended environment:  OCR routing will achieve approximately 70% accuracy.  This means that it will alleviate, but not eliminate the routing burden.  It will work in smaller companies/departments where received faxes are typewritten.  For obvious reasons it will not be able to distinguish between users with the same name.

Line routing

Line routing allows to assign a physical fax line to a user.  For example, if your office had 4 fax machines in each department prior to purchase of GFI FaxMaker, you could use those 4 fax lines with 4 fax modems to route the faxes to each department based on the number on which it was received.
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  • Two or more physical fax lines
Recommended environment:  Highly recommended for environments where routing a fax to a specific department or workgroup is sufficient.

Routing a fax using DTMF/DID routing

The system works in the following way:
  1. The caller dials the fax number and waits until the call is answered
  2. The fax card/modem will now transmit a tone, after which the caller/PBX must enter the DTMF routing number
  3. The GFI FaxMaker fax server will recognize the DTMF number and use it to identify the recipient of the fax
DTMF routing is most frequently used in combination with a voice modem and a PBX that supports DID/DTMF conversion.  In this case, you can use excess DID lines from the PBX to route the fax to an extension.

The PBX will convert the DID tones to DTMF and forward them to the modem after the modem beep.  Most common PBXs support the conversion from DID to DTMF.
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  • A GFI Software supported modem that supports a voice chipset OR a Dialogic Brooktrout fax card.  If a PBX is used, the Network Administrator should have advanced technical telecommunications knowledge to operate and program the PBX.
Recommended environment:  Only in specific environments where a special PBX is available or where one can explain to the callers (i.e. the senders of the fax) how to input the DTMF number.

Note: Do not enable DTMF/DID routing unless you have a compatible voice modem or a compatible ISDN/fax card correctly set up.  Compatible voice modems are modems that have a Rockwell voice chipset.  You must also select the corresponding driver in Modem properties as Voice modem (Rockwell). If you enable DTMF routing without having a voice modem or an ISDN card, the fax server will generate an error while receiving.

What is DTMF? - DTMF (Dual Tone Multi Frequency) tones are generated by a telephone handset, and can be used to identify a recipient.  DTMF uses two tones to represent each key on the touch pad.  When any key is pressed, the tone of the column and the tone of the row are generated, hence dual tone.  As an example, pressing the '5' button generates the tones 770Hz and 1336Hz.

CSID routing

CSID (Caller Sender Identification) relies on the FAX ID, which a FAX machine/FAX card displays when sending a fax.  Since it rarely changes, it can be used to identify the sender and thus the corresponding recipient.
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Recommended environment:  Only in specific environments where each user faxes to different companies.  For example, if your sales and support people both interact with the same company, then CSID routing is not recommended.

Manual routing

When no recipient can be determined for a fax, the faxes are routed to a designated mailbox, from where the inbound fax router (a person designated to route faxes) can view the fax and select the right recipient.  This mailbox can be the mailbox of a particular user, or it can be an Exchange public folder.


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