General DSL Questions

  • Do Excelsus filters comply with FCC Part 68 rules?
  • Yes, these products comply with Part 68 of the FCC rules and the requirements adopted by the ACTA. On the product is a lable that contains, among other information, the FCC registration number and ringer equivalence number (REN). Download a PDF of the complete Customer Information statement.
  • What are filters and why do I need them?
  • DSL uses the high frequency bandwidth of your existing telephone lines to transmit and receive data. Excelsus Z-BLOCKER┼¬ 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. Excelsus 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.
  • I have just signed up for DSL. My DSL service provider sent me a self-installation kit with a modem and filters. What do I do with the filters?
  • Install a filter for each telephone device in your home. Simply disconnect each telephone from the wall, plug a filter into the phone jack at the wall and plug the cord from the telephone 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, 56k 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.
  • My self-installation kit does not have enough filters. How do I get more?
  • If you need more than five filters in your home, order a dynamic filter (Z-275P2J) for all additional single-line phones beyond the first five. Use a dual-line filter (Z-D250) on two-line phones. Additional filters for Canada and the U.S. can be ordered online, under the North American section of the online store. Filters for other regions can be ordered by emailing our sales department.
  • What if I don’t put a filter on every telephone device?
  • 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.
  • Can I filter multiple devices with only one filter?
  • Yes, the fax machine, telephone, answering machine and Caller ID box could all share the same filter by simply plugging a twin-jack adapter into the filter’s phone port (Excelsus model A-2L). Then plug two or more devices into the adapter.
  • What filters should I use for my two-line phone?
  • 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 and reduced voice quality. Order the Excelsus Z-D250″dual line” filter. It filters both lines for one or more phone devices sharing a single jack.
  • DSL is interfering with my alarm system. Do you make a filter for my alarm system?
  • Yes. The Excelsus alarm panel DSL filter (model Z-A431PJ31X-A) uses advanced Z-BLOCKER┼¬ 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 alarm filter supports the alarm system’s ability to take custody of the phone lines (“line-seizure”) while maintaining the high-speed data link to DSL and HPN devices in the home. The alarm filter is compatible with every major home alarm system and interfaces with the alarm panel via the RJ31X – RJ38X (or Canadian equivalent) jack. The alarm filter won the prestigious Product Achievement Award at the ISC Expo’s New Product Showcase in New York in August 2001. Excelsus also offers a version with screw terminals (Z-A431EU). Excelsus alarm filters are available through licensed alarm service providers and security industry distributors. DSL customers, please contact your local alarm service provider for ordering information. Alarm dealers, please contact your favorite distributor for further information or email us for further assistance.
  • What is a convenience jack?
  • Typically an ADSL modem has to be connected directly to the phone jack providing DSL service. If the user wants to use a phone at the same workstation as the modem, they must run the phone cord from another phone jack, which is often on the other side of the room. Many Excelsus DSL filters provide a “convenience jack” so that users can connect both a phone and a modem to a single phone jack. The filter has two jacks: one that is filtered for the phone device, and one that is unfiltered for an ADSL modem or HPN device. A convenience jack eliminates the need for a separate “Y” adapter or a 2-line adapter.
  • I am a current DSL subscriber who is moving to a new location. When I first had DSL installed, I didn’t need filters. Why do I need them now?
  • In the past, DSL service providers would send a service technician to your home to install DSL. They would install an ADSL/POTS splitter and activate DSL service at only one phone jack within the home. If you wanted to relocate the computer that used DSL, it required another service visit. To eliminate customer’s having to wait for a service visit, the DSL providers have developed self-installation kits that include filters. Now when you want to activate DSL service or move a computer, installation is quick and easy. This eliminates a service call, reduces the time required to activate your DSL service, and allows you to put your DSL computer connection at any phone jack in your home.

Problem-Solving / Troubleshooting Questions

  • Whenever my DSL modem is turned on, there is noise on the telephone. What is happening and how do I fix it?
  • This problem can have several root causes:
    1. 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.
    2. The cord between the DSL modem and the wall jack may be a standard flat telephone cord. In these cords, one line acts as a broadcast antenna and the other acts as a receiving antenna, picking up noise. This is known as cross talk. We recommend replacing the standard flat cord with a twisted pairt elephone cable (model CDPT-25, CSPT-14 or CSPT-7).
    3. Cross talk may be occurring in the standard flat cord that connects a telephone, fax machine, or other device to the wall jack. By placing a Z-BLOCKER┼¬ filter at the jack where an analog device plugs into the wall, the device and flat cord will be isolated from modem activity.
    4. Homes with twisted pair cable are protected from cross talk. Homes using standard flat cord or quad twisted cable have little or no protection against cross talk. The only solution for those homes is to have the DSL provider install a splitter where the line comes into the house to put the modem on its own isolated line.
  • I installed the filters and now my DSL data service is not working. What should I do?
  • Excelsus filters should be installed on all of the analog telephone devices in your home. However, your DSL modem should be plugged directly to the jack, or the DSL/HPN side of the filter. Check to make sure that the cord from the DSL modem to the wall does not pass through the filter’s phone port; if the modem is plugged into the phone side of the filter, the DSL modem will not “sync” up. If you still have trouble with your service, contact your DSL provider for assistance. After I installed the filters, my Caller ID service quit working. How can I fix this?
  • Filters increase the capacitance (the stored electrical charge) on your phone lines. Caller ID works by sending a signal between ringing intervals via frequency shift keying, which can be affected by higher capacitance. If the capacitance is too high, the Caller ID unit will not be able to read the incoming signal. The Excelsus dynamic filter (model Z-275P2J) is activated only when the phone is off-hook, minimizing capacitance and allowing the Caller ID signal to pass through more easily. The dynamic Z-275P2J should also be used for all additional single-line phones beyond the first five.
  • I have two phone lines coming into my home. Why did line two go dead when I installed the filter?
  • You’re probably using a single-line filter, which cannot pass line two. You need a dual-line filter (Z-D250P2Jor Z-D250CWA) which isolates both line one and two from the modem.

Technical Questions

  • Why does Excelsus recommend the dynamic filter if I have more than five phones?
  • Filters increase the capacitance (the stored electrical charge) on your phone lines. When there are more than five Excelsus filters on the phone line, the increased capacitance may cause noise and loud sidetone in telephone handsets. Increased sidetone occurs when your own voice is transmitted back to your own receiver louder than normal and may have an echo-like effect. It also reduces the volume at which your voice is transmitted to the party you’re speaking with. With increased sidetone, you may feel like you are speaking very loudly while the person on the other end of the line can barely hear you. Excelsus designed the dynamic Z-275P2J filter to actively filter only when the phone is off the hook, minimizing the capacitance that is added to the phone line. The dynamic filter is compatible with all Excelsus filters, so you can use a mixture of these models. Just be sure to use the dynamic Z-275P2J for all additional single-line phone jacks beyond the first five.
  • I have one phone line coming into my home with both DSL service and my normal telephone service. My modem instructions say that the modem must be connected to line two in order to work. What can I do?
  • Earlier models of DSL modems marketed in the United States and Canada were designed to connect to phone line two. Use the Excelsus dual-line swapper (model S-L1/L2). It plugs into the DSL modem so that it will connect on line one of your telephone service.
  • I have three or more phone lines and/or a PBX key system, which do not work with the filters. What can I do?
  • Install one filter or splitter ahead of all your telephones. This requires a separate wire pair to be run directly from the Network Interface Device (where the phone line connects to your home from the outside) to the phone jack connecting the DSL modem. Download a PDF of a diagram of this installation.