1.14.2 Fax

Fax server is a service enabling customers to send and receive FAX messages directly from VUC or VUP portals as well as over email clients by Fax2email and Email2FAX services. Correct operation of the service depends on several related applications. Before setup it's worth to read the manual to the end in order  to understand the mechanism of the service and reduce the risk of mistakes in the individual configuration steps. 

Overview

Fax Receive - A customer having DID number with support for T38 protocol may allocate the number ( using portal interface) to a service named FaxBox - creating this way his own virtual FAX.

From now on, calls to so-configured DID number will be automatically switched to the fax signal handled by VoipBox with a scenario named "Fax Receive". 

Received FAX message will appear in the user portal immediately after transmission is completed.

If customer had filled his email address under personal data of his account, the FAX message will be sent as an attachment to the email by Fax2Email service.

Fax Send

Fax message can be sent by  a user from VUC or VUP portal interface

as well as over an email message by Email2Fax service if sender address is authorized on customers account settings.

Fax messages sent from portal and by fax2email service are being converted by ImageMagick (third party) application to .tiff format, then placed to a customer directory under VoipBox structure.

Next, the system will trigger a task that initiates a call to a destination number and after  the call is established, it joins the call with T38 transmission handled by VoipBox over Fax Send scenario.

Setup

• The mandatory condition for Fax server is support for T38 protocol by carriers:
  DID (inbound) - for Fax reception
  Termination - for outbound Faxing
• Make sure that Fax service customers, Wholesale Client of DID carrier and termination gateway are enabled to use T38 transmission codec.

Technical prefixes, number manipulation rules, tariff

• The service requires one technical prefix, which is used to bridge outbound Fax calls with T38 transmission handled by VoipBox over Fax Send scenario
  It's worth to create prefix consisted of letters instead of numbers in order to prevent possible conflitcs on routing with calls sent to external gateways. It's also easier to identify purpose of so-defined prefix. In this manual we will use a prefix named literally: faxsend
  
• To every outbound Fax number, the system appends a prefix: 'fax#'  in order to separate T38 traffic from standard voice traffic on routing layer so that the Fax traffic can be sent to a separated gateway or group of gateways with T38 support. In this manual we assume one gateway dedicated for fax calls, therefore  routing plan needs one prefix:: fax#  which leads to a termination gateway supporting T38 transmission. 
  
  It's important to remove the technical prefix 'fax#' before calls leave the softswitch, so that sip URI of calls sent to an external gateway contain only numbers, without the technical part (fax#) which would prevent them from correct routing by a termination carrier. This can be done on the gateway settings (advanced tab).
  
  The technical prefix 'fax#' needs also to be included in clients tariff and/or number manipulation settings, It's important to know that  the system processes Fax calls, using callback mechanism. From technical point of view, a destination fax number is considered by the system as callback source number, while the  'fax send' scenario prefix is considered by the system as callback destination number. Therefore the relevant place to adjust number manipulation rules for Fax calls is under Source dialing and Source tariff rules on client settings -> advanced tab.
  
  Basically there are 2 options regarding how to configure client tariff :
  - Fax calls charged by same rates as voice calls - in this case, the technical prefix 'fax#' should be removed by source tariff rules  on clients account settings, so it will look like: fax#->
  It's worthwhile to consider different habits of customers regarding format of chosen number so that calls to numbers defined in different format than E164 were not rejected by the system due to no match between chosen number and tariff. The most common rule will look like: fax#+-> OR fax#00-> OR fax#0->CC OR fax#-> while CC must be replaced by a default country prefix, when customers define their desired number using local format.
  - Separated set of rates for Fax calls - in this case, all A-Z prefixes, same as for voice rates, should be added/imported to clients tariff with an additional prefix 'fax#'. In order to allow customers to use different formats of destination number, source tariff rules  should be set similarly as on point above, without removing prefix 'fax#', so it should look like: fax#+->fax# OR fax#00->fax# OR fax#0->fax#CC while CC must be replaced by a default country prefix, when customers define their desired number using local format.
  
  For both above options, the common rule for routing purpose set on source number rules which includes adjustment for different formats should look like: fax#+->fax# OR fax#00->fax# OR fax#0->fax#CC while CC must be replaced by a default country prefix, when customers define their desired number using local format.
  Clients tariff must contain prefix of fax send scenario with free voice rate, according to this manual it is prefix 'faxsend'.
  
  VSservices
  Configuration file: C:\inetpub\wwwroot\VSServices\AppSettings.config contains a key with number of fax send scenario. It should match the actual configuration, according to this manual it should be: <add key="fax_sent_number" value="faxsend" />
  Just in case, make sure that Imagemagick application has been installed under patch defined in a key fax_image_magick_path.
  All other Fax related keys should stay with their default values.
  
  Fax2Email
• Execute C:\Program Files (x86)\VoipSwitch\FaxToEmail.Desktop\FaxToEmail.Desktop.exe and press the "Start" button on its interface, the application should remain in running state
  Service reads SMTP settings stored in: VSM: Settings : Billing : Invoices : Mail settings, make sure this section contains right SMTP details.
  Configuration keys are stored in a file: FaxToEmail.Desktop.exe.config, placed in application directory. Usually there is no need to edit them, as this should have been done by installer.
  
  Email2Fax
• Under your own domain, create two records for new subdomain:
  -A type i.e.: fax,yourdomain.com pointed to fax server IP
  -MX type pointed to previously created subdomain
  The DNS domain is not mandatory for the service, but many email carriers may reject messages sent to IP address.
• Execute C:\Program Files (x86)\VoipSwitch\VS.EmailToFax\EMailToFax.exe then press the Edit button on its interface and fill listed forms:
  Domain name: the name of created subdomain
  Listen interface: fax server IP
  Port number: default 25
  Save changes with the "Update" button and press Start. The service should remain in running state
  Configuration keys are stored in a  file EMailToFax.exe.config placed in application directory. Usually there is no need to edit them, as this should have been done by installer.
  Please note that the service doesn't convert email attachments, therefore the intended fax content should be included directly in an email - not as attachment.
  
  After all steps are done, it's time to test the service.