There's a Crackling or 'hum' noise on my phone line

dean.huczok —  February 22, 2011

      If you’re experiencing a ‘hum’ or crackling noises on your phone line, chances are the fault is inside your premises. Most people blame their service provider, who then pass the blame back onto the customer after their servicemen check the network. This can be a terribly frustrating process which usually ends with both sides blaming each other, with no conclusion or solution to the problem. There are a few things we recommend you do before logging a fault with your service provider, to save time and avoid headaches.

      The first thing to do is to see if your equipment is causing the problem. To do this, simply disconnect everything from the phone line: unplug your modem, fax, phones, etc from all sockets. Then plug in just your phone, and check for the noise. If you still hear the noise, ask your neighbour if you can borrow their phone for a few minutes (you never know, the phone you are using may be faulty!). If the noise has stopped, plug one piece of equipment in (start with the modem) and check the line again for noise. Repeat this with your other equipment, like the fax machine and other phones, until you hear the noise again, and the culprit is revealed. You might find the fax machine, or perhaps an old cordless phone is causing the noise.

      Other things to check are the leads, filters, adapters and sockets. Crackling noises or a constant ‘hum’ on the phone line can be caused by many factors, the most common being moisture and physical damage. First, inspect the plugs on your phone leads connecting your socket to your phone, fax, ADSL modem, etc. for corrosion (a green/blue powder) or physical damage (for example, the contacts may have burned out, due to a lightning strike or power surge). The contacts should look clean and shiny, with no discloration of the surrounding plastic. Check the cables for any physical damage, like cuts in the cable, areas where the insulation has come off, and sharp bends or knots (which can damage the conductors inside). Corroded or damaged cables can cause noise on your line, and even slow your internet connection.

      The same goes for any ADSL inline filters, adapters, and sockets you have in your premises. Check each for physical damage (especially if it is loose or hanging off the wall by the wires!) and visually inspect all metallic parts for signs of corrosion; but please, do not by any means, unscrew/open your phone sockets, as there may be hazardous voltages inside. By Federal Law, only a qualified technician shall inspect the inside of phone sockets and fixed cabling inside your house that is connected to the telecommunications network. Cabled Up has a team of ACMA licenced technicians who service the Sydney metro area.

      If you find corrosion or damage on your phone leads, ADSL filters or adapters, replace them as soon as possible. Even if they’re not the source of your problem, they will definitely cause problems down the track, and are fairly inexpensive to replace.

      If the noise is still there, even with everything unplugged, you have two choices: You can call your Service Provider, as there may be a network fault; or you can have your internal cabling checked (including sockets and junctions) which may be causing the fault. Just remember, your service provider will only check the network up to the Network Boundary (which could be an NTD outside your home, an MDF, or the first socket inside your premises). If there is no fault up to that point, they will tell you to organise a private technician to have your internals checked. They may offer to charge you a Fee For Service, but be warned they do charge a premium for call outs.

      We have seen many internal faults where wires have been twisted together inside the wall cavity and become corroded, and where cabling has been run under the carpet across a doorway or thoroughfare and been crushed after months/years of being stepped on. But the most common of all, especially in the coastal areas, is the corroded socket. To check for internal faults or to replace sockets, contact a few licenced technicians and get quotes (The Whirlpool Forums have a Wiki page with a list of Licenced Cablers, organised by state, with links to contact information). Cabled Up are professionals in this line of work; you can contact us for a free quote, or ask any questions you may have about the problem you’re experiencing.

Dean Huczok

dean.huczok

Posts

With a love of physics, electronics, and programming, telecommunications was Dean's obvious career choice. His understanding of the underlying technology enables him to be a valuable asset to the team.