The VoicePro includes the capability to detect incoming fax calls. When this feature is enabled, it will route those calls to your fax machine.
The VoicePro saves you from the need of having a separate fax line since it will handle regular voice calls as normal, and it will send fax calls to your fax machine.
If you want to use your fax machine on a dedicated line, then there is no need to program the fax detection. But if you want to share your phone lines to be used as both fax and voice, then you would connect your fax machine to one of the extension jacks on the VoicePro and enable fax detection.
How To Program Fax Detection
Once you connect your fax machine to a chosen extension jack, you also need to enable Fax Detection and specify where you connected your fax machine so it routes those calls correctly. Incoming fax calls will automatically be routed to that extension where you have your fax machine connected.
To enable Fax Detection with the VoicePro you need to do the following...
- Use function 31 to specify which CO lines may receive incoming fax calls. This causes a slight delay when answering, in order to wait for a CNG signal that is sent by the sending fax machine.
- Use function 7 to specify the extension where you connected your fax machine.
When the VoicePro detects a fax CNG signal on any of the lines you specified in step 1 above, the call is automatically routed to the extension you specified in step 2.
If no fax CNG signal is detected, or if the caller makes a regular voice call, then the Automated Attendant will answer the call. In that case the caller can manually dial any extension or press keys for any menu option you created.
Fax Detection Overrides All Other Call Routing Assignments
When you enable fax detection, the VoicePro is forced to use the Auto Attendant to process the routing. This means that if there is no fax detected then the Auto Attendant company greeting will play to the caller, and he or she can select from the menu options you provided.
For this reason it is important to understand that fax detection overrides any other call routing you try to program that would cause a conflict.
More specifically, if a fax tone is detected the call is automatically switched to the extension where you have your fax machine (specified with function 7).
Enabling fax detection with function 31 overrides functions 4, 27 and 30 since the Auto Attendant will answer the call if it's not a fax.
Function 4 is used to program ringing assignment (which phones ring) before the Auto Attendant. Most people don't use this since they want the Auto Attendant to answer and handle all calls.
Function 27 is used to disable the Auto Attendant. But when you enable fax detection you are forcing this back on.
Function 30 is used to specify how many times the phones should ring before the Auto Attendant answers. But, again, when you use fax detection you are forcing the Auto Attendant to handle all calls on the fax line, therefore making this function meaningless.
Bottom line: If you want to bypass or delay the Auto Attendant, you cannot also use fax detection.
How Fax Machines Work
Fax machines communicate with one another before starting the data transmission. The originating fax machine sends a CNG signal (1100 Hz) to indicate that this is a fax call. Then the receiving fax machine sends back a CED tone (2100 Hz) to say it's ready to receive. This is known as handshaking.
If you connect your fax machine to an extension jack on the VoicePro, and you enable fax detection as explained above, then the VoicePro will 'listen' for the CNG fax signal before the auto attendant answers.
- If it does not hear a CNG fax signal, it will handle the call as a regular voice call.
- If it hears the CNG signal then it immediately passes the call to your fax machine, along with the Caller-ID if you have that service.
Your fax machine will then detect the repeating CNG signal and 'handshake' by responding with a CED tone (2100 Hz) to indicate that it's ready to receive the transmission.
Special Considerations
Delayed answering while waiting for fax:
When fax detection is enabled, there will be a short delay before the auto attendant answers. This is because the VoicePro is listening for a CNG signal, which is what a fax machine sends to make itself known.
If no CNG tone is received after a few seconds, then the VoicePro will answer the call and handle it as a human caller. It will play your company greeting and wait for the caller to dial an option.
Missing CNG Tone with incorrect voice dialing:
Some people make the mistake of dialing the destination fax number with the fax machine's handset off hook. The VoicePro will incorrectly detect this as a voice call.
The sender needs to press the "Send Fax" button on their machine, or simply dial without using the handset, in order for the VoicePro to properly know this is an incoming fax.
If the call was determined to be a voice call because the originating fax machine did not send the CNG signal within the first few seconds, then it's too late for the caller to switch to fax mode. This is why it's important to not call by voice first.
How To Send a Fax
You can use your fax machine to send faxes, as you normally would do. When it starts to send a fax, the VoicePro will automatically provide dialtone on any available outside line.
If you want to force your faxes to always go out on a specific line, program the extension where you connected your fax machine so that it will always select that line for outgoing calls. Use Program Function 3 to specify which outside lines can be accessed from each extension.
