http://www.chrispearson.org/pages/articles/fax.asp
09h41
Wednesday, 8. October 2008

INBOUND FAX PROCESSING

Contents

Reception of faxes and routing to an intranet web site

Options for routing received faxes

ISDN/DDI routing

ISDN
DDI

OCR routing

DTMF routing

CSID routing

Manual routing


Reception of faxes and routing to an intranet web site

Applications and hardware are now generally available which allow faxes to be received and distributed across local- and wide-area networks. Placing fax images on an intranet web site makes them easily available to users - Exactly the same technology can be used to publish them to an internet site, so long as security is properly implemented.

Using SuperFax - which comes free with US Robotics modems - and a suitable TIFF generator - PeerNET TIFF is available on the web for about £55, for instance - faxes can be received to a server without human intervention.There are plenty of viewers available to look at TIFF images - The Wang Image executable comes with Windows and makes a good default viewer with adequate print options.

An overview of how these applications can be integrated is shown in the diagram below:

If there is only one 'phone line then the application can be very simple: all faxes will be placed in a communal in box - much like a physical fax machine.

This is a typical implementation:

The typical applications provide a virtual fax machine for a user group, with everyone's faxes stored together in a common network repository - the in box.

Incoming faxes are directed to a published exchange line or DDI number, to which is connected a FaxModem. Fax reception is managed by SuperFax v6.

No Windows dial-in is configured and SuperFax is set to allow only incoming fax connections. This will prevent dial-up data connections being made to the server.

SuperFax is configured to automatically print all incoming faxes - The output is printed to a TIFF image driver called PeerNet ETIFF which itself is configured to save .TIF images of the received faxes into a named directory.

Microsoft Internet Information Server (IIS), also running on the server, maps a virtual web directory to the fax images. A web application using active server pages (ASP) coded in VBScript lists out the received faxes and provides hyperlinks to view the fax images. This can be found, say, on the intranet web site at http://servername/fax.

Viewing can be achieved with any suitable application - The Wang Image application is bundled with Windows (TIF files should be associated with, typically, C:\Program Files\Windows NT\ImageVue\wangimg.exe.)

A management option to delete viewed faxes should also be available to allow users to manage their housekeeping.

 

Below I have rounded up the practical options, together with some guidelines on UK pricing, that you might consider when implementing on-line fax processing.

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Options for routing received faxes

An important aspect of a network fax solution will ultimately be its maintenance of privacy.

Routing faxes to their intended recipient requires the identification of the addressee. There are six basic options available, listed here from probably the best option through to the worst:


1 ISDN/DDI routing
2 OCR routing
3 Line routing
4 DTMF routing
5 CSID routing
6 Manual routing

The requirements for, and merits of, each are covered below, together with an indication of the costs involved in their implementation.

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ISDN/DDI routing

Both ISDN and DDI (Direct Dialling Inwards, sometimes also called DID) both allow and require each fax user to have their own incoming fax number. This is the only option where routing can be guaranteed to be 100% infallible: It is also the best option for integration with email since each user has their own fax number and their own email address.

This is the option used in most network-enabled fax solutions (RightFax, for example), especially those which integrate with mail servers.

 

ISDN

The incoming fax is sent to a user's individual number and the receiving number is passed from the ISDN card to the fax server. The server application looks up the user's identity using the ISDN number as a key.

 

The fax image is then either forwarded as a mail attachment using SMTP or written to the user's personal folder on a web site.RequirementsISDN line with multi-subscriber numbers (MSN)

ISDN CAPI 2.0 card

Costs

ISDN MSN £1000
BRI CAPI 2.0 Server £500

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DDI

The incoming fax is sent to a user's individual number which is likely to be a DDI number on the existing group.

The DDI number (effectively, the switchboard extension being used) is passed from the DID card in the switchboard to the fax server. In exactly the same way as in the ISDN example, the server application looks up the user's identity using the DDI number as a key.

The fax image is then either forwarded as a mail attachment using SMTP or written to the user's personal folder on a web site.

Requirements

DDI group - An addition to current switchboard capacity, if necessary
DID card

Costs

DID card - Brooktrout TR114 is typical, at about £2500
   

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OCR routing

Faxes can be routed by software which reads the recipient's name from the fax image. Optical character recognition (OCR) can identify users by first name, family name, job title or other parameter.

Some OCR suppliers claim a 70% reliability for identifying recipients of incoming faxes: This generally assumes that the documents are computer-generated or typed. There is an obvious impact in cases where the document's structure is unusual.

Despatch notes, invoices, proofs of delivery are all good candidates for OCR processing where the documents are standard and the eventual routing should be transparent to the originator.

Where document presentation is uncontrolled, OCR routing cannot, realistically, be recommended.


Incoming faxes can be received on a single line (multiple lines may be used) and rendered as TIFF images. OCR software processes the image file generating a parameters file and moving the TIFF image to either a processed documents folder or a failed documents area.

 

Requirements

OCR software
Typed or printed documents with standard format(s)

Costs

OCR software - Hands and Eyes Lite from ROCC is £7000
Modem - £100
Exchange line - £100

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Line routing

Line routing is implemented by giving each user their own virtual system serviced by their own physical telephone line.

Each user has a dedicated exchange line, a modem and a fax application running on a server.

This option is ideal - and highly cost-effective - for small workgroups of two, three or four to perhaps six users.

Routing is 100% reliable.


Each users' faxes are sent to their own number, answered by their own modem.
Fax reception software dedicated to that modem port renders the fax image file, forwarding it as a mail attachment or posting it to the user's web folder.
It is possible, and often convenient, to run a fax client on the user's PC with the modem configured as a shared resource on the server. This allows users to both send and receive faxes on their dedicated line.

Requirements

One exchange line per user
One modem per user
One fax application per user

Costs

Exchange line - £100
Modem - £100
Application - SuperFax is free

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DTMF routing

DTMF uses the multi-frequency signals available in tone dialling: Dial-tone multi-frequency.

Typically the modem used must be a combined voice/fax type.

The originator must input the routing key. This is the major disadvantage of using DTMF routing: The originator must know

That the DTMF routing key must be sent
How to send the routing key
What the intended recipient's routing key is

Also, if a private branch exchange is involved, the switch must be configured to allow the DTMF key to be passed through the exchange to the extension to which the modem is connected.


Incoming faxes are sent to the private branch exchange and routed to an extension on the exchange, either by auto-answer and extension selection, by manual transfer or by DDI.

Once connected to the fax modem the originating fax station sends the recipient's routing key: This will usually be manually keyed by the originator.

Requirements

Voice/fax modem
Suitable PBX programming and configuration
Properly briefed originators

Costs

Voice/fax modem - £100
PBX programming - £1000 if not programmed by internal personnel

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CSID routing

CSID - caller identity or CLI (caller line identity) - routing is based on recipient's getting faxes from defined originating numbers.

This technique is sometimes implemented as a routing backup in network fax implementations, making a second, best-guess when another routing technique has failed.

If two recipients are likely to receive documents from the same originating number (highly likely) then this technique is not recommended.


The originating fax station connects to the modem without withholding the caller's number.

The caller's number is passed to the server and matched to a recipient. The fax is rendered as an image file and either posted to the relevant web folder or forwarded as an email attachment.

Requirement

Originator must use a service which supports CLI
Originator must not suppress own number on calling

Costs

CLI option on exchange line - £10
Modem - £100

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Manual routing

There must be a manual routing option in any network fax solution, allowing faxes which fail automated routing to be processed.

 

Also, where confidentiality is not an issue, all faxes may be saved to a communal in tray and individual users can locate and manage their own faxes while, perhaps, forwarding documents to colleagues on an ad hoc basis.


Requirements

Modem
Exchange line or DDI line

Costs

Modem - £100
Exchange line - £100

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