Voice over IP
(VoIP) services provide normal telephone service (usually long distance) through a broadband Internet connection rather than the standard telephone network. These services use packets to break up the voice signal on a phone line and transmit it digitally to the receiver where the packets are reassembled.
Because HP fax products are designed to work with ordinary analog phone service, HP cannot guarantee that the HP fax product will work with a VoIP service.
Faxing with VoIP services
These services are often not compatible with fax machines unless the provider explicitly states they support fax over IP services.
Although a fax may sometimes work on a VoIP network, it may fail for the following reasons:
Fax transmissions are sensitive to the timing of signals.
There is a slight delay in the signal because of the time it takes to create the Internet packets.
Internet traffic becomes heavy and packets are lost which then have to be recreated.
Heavy Internet traffic also increases latency (the time it takes for a packet to travel from its point of origin to its point of destination) which then exceeds timing requirements.
How to dial *xx codes when faxing
When sending a fax, it may be necessary to enter in a *xx code as the first part of the number. Follow the steps below to dial *99 when using a VoIP service.
NOTE:Since the *xx code is an instruction to the phone system, this must be dialed live.
To pick up the line on the HP All-in-One, press Start Black Fax
or Start Color Fax
without entering a phone number first.
When you hear the dial tone, enter in the *99
Wait a few seconds and then enter in the rest of the number.
The HP All-in-One will complete the fax as normal.
What can be done to help the fax transmission?
The communication speed is a major factor in fax transmission over VoIP. Currently there are three speed standards.
Fast - v.34 which communicates at 33.6 Kbps.
Medium - v.17 which communicates at 14.4 Kbps
Slow - v.29 which communicates at 9.6 Kbps
Changing the Fax Speed Adjustment setting to Medium may improve your ability to send a fax over a VoIP network. On most HP fax products the connection speed can be set to a lower speed. Those that do not have a Fax Speed setting generally communicate at medium speed or lower as this was the past standard. Consult your user's manual for information specific to your model.
Changing the Fax Speed Adjustment to a lower speed
Follow the steps below.
Select Advanced Fax Setup
Select Fax Speed
Try the fax again.
If you continue to have problems faxing, contact your VoIP provider as they may have options to improve the ability to send and receive faxes over VoIP telephone service.