HP LaserJet Pro 300 Color MFP M375 - Manual (Page 207)

The HP LaserJet product is an analog device that is not compatible with all digital phone
environments (unless a digital-to-analog converter is used). HP does not guarantee that the product
will be compatible with digital environments or digital-to-analog converters.
DSL
A digital subscriber line (DSL) uses digital technology over standard copper telephone wires. This
product is not directly compatible with those digital signals. However, if the configuration is specified
during DSL setup, the signal can be separated so that some of the bandwidth is used to transmit an
analog signal (for voice and fax) while the remaining bandwidth is used to transmit digital data.
NOTE: Not all faxes are compatible with DSL services. HP does not guarantee that the product will
be compatible with all DSL service lines or providers.
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.
ENWW Use fax 191