HP LaserJet Pro 500 Color MFP M570 - Manual (Page 148)

A typical DSL modem employs a filter to separate the higher frequency DSL modem communication from
lower frequency analog phone and fax modem communication. It is often necessary to use a filter with
analog phones and analog fax products that are connected to a telephone line used by a DSL modem. The
DSL service provider usually provides this filter. Contact the DSL provider for more information or for
assistance.
PBX
The product is an analog device that is not compatible in all digital phone environments. Digital-to-analog
filters or converters may be needed for faxing functionality. If faxing issues occur in a PBX environment, it
might be necessary to contact the PBX provider for assistance. HP does not guarantee that the product will
be compatible with digital environments or digital-to-analog converters.
Contact the PBX provider for more information and for assistance.
ISDN
The product is an analog device that is not compatible in all digital phone environments. Digital-to-analog
filters or converters may be needed for faxing functionality. If faxing issues occur in an ISDN environment, it
might be necessary to contact the ISDN provider for assistance. HP does not guarantee that the product will
be compatible with ISDN digital environments or digital-to-analog converters.
Use fax on a VoIP service
Voice over internet protocol (VoIP) services are often not compatible with fax machines unless the provider
explicitly states that it supports fax over IP services.
If the product experiences problems getting a fax to work on a VoIP network, verify that all cables and
settings are correct. Decreasing the fax-speed setting might allow the product to send a fax over a VoIP
network.
If the VoIP provider offers a "Pass through" mode for the connection, that will offer better fax performance
on VoIP. Also if the provider has "comfort noise" added to the line, fax performance can be enhanced if this
feature is not enabled.
If faxing problems continue, contact the VoIP provider.
Fax memory contents are retained when there is a loss of power
The flash memory protects against data loss when a power failure occurs. Other fax devices store fax pages
in either normal RAM or short-term RAM. Normal RAM immediately loses data when power is lost, while
short-term RAM loses data about 60 minutes after a power failure occurs. Flash memory can maintain its
data for years without power applied.
Security issues when connecting internal networks to public phone lines
The product can send and receive fax data over telephone lines that conform to public switch telephone
network (PSTN) standards. The secure fax protocols make it impossible for computer viruses to be
transferred from the telephone line to a computer or network.
The following product features prevent virus transmission:
134 Chapter 7 Fax ENWW