A: DSL uses the high frequency bandwidth of your existing telephone lines to transmit and receive data.
DSL filters are "low-pass" filters, which means that they allow the low frequency signals (voice) to
pass through, while blocking the high frequency signals (data) from traveling through the phone
lines to your telephone. Without the filters, the high frequency data signals would be heard on your
phone as static and noise, and would diminish the quality of your voice and data services. DSL
filters protect your telephone voice quality and keep your DSL service operating at optimal speeds.
Excelsus makes a variety of filters for different applications, such as wall-mounted phones and
dual-line phones. Please use our Product Wizard to determine which filters you will need.

A: Install a filter for each telephone device in your home. Simply disconnect each phone from
the wall, plug a filter into the phone jack at the wall and plug the cord from the phone
into the phone jack of the filter. Do this for every analog device connected to your phone line.
Analog devices include all answering machines, telephones, fax machines, Caller ID boxes,
modems, and cable or satellite television subscription boxes that connect to the phone line.
Don't forget the phone in the garage, basement, or outside by the pool! See this graphic image
for a diagram of how this will look when it is set up.

A:Unfiltered phone devices can cause noise on all phones, even if they are filtered. This
is because unfiltered phones can transmit low-frequency DSL artifacts back onto the phone
line. The artifacts are within the voiceband frequency range, and pass through the filters
as part of the voice signal. Therefore we recommend that all phone devices have filters.

In two-line installations, one line carries voice and the other shares DSL and voice. Both lines require filters, otherwise the shared line will exhibit noise. Order the 2Wire LFT4-2 "dual line" filter. It filters both lines for one or more phone devices sharing a single jack.

Yes. The Excelsus alarm panel DSL filter (model Z-A431PJ31X-A) uses advanced technology
to protect the residential and small business alarm system telephone service (POTS)
interface, which dials out to the alarm company in the event of an emergency. Without
this protection, alarm panels on DSL or HPN lines may have difficulty reporting incidents.

The filters may be bad but probally are of a lower quality. When you have that many
telephones on the same line it will excessively degrade the DSL signal causing the problems you mentioned. You need a higher quality filter that meets ANSI T1.421 standards for voice quality
and data performance with five filters on the line. The Excelsus Z-330P2J ANSI DSL filter is a high performance single line DSL filter that meets the tough ANSI T1.421 spec with up to five
phones on the same line. Excellent voice quality and performance.