5 (for the voice) and 3 (for the ringer). Having said this, most modern telephones no longer require a ringing capacitor may have 2-wire connections, which means that extension wiring can usually be run with only pins 2 and 5. Often where multi-core cable is used, the remaining cables are used for wiring extensions on additional incoming telephone lines. Broadband In order to use broadband Internet services simultaneously with voice telephony, it is necessary to use a DSL filter. This is a low pass filter in line with the phone outlet. This prevents high frequency data noise from affecting the lower frequency voice bandwidth and it also prevents the low impedance of the connected phone from attenuating or modulating the high speed DSL data Path. Enough bandwidth is retained for voice telephony and the majority is used for high speed data. All phones (or other voice band devices) must be connected via a filter (either a separate filter for each phone or one filter covering multiple phones) to avoid interference between the phones and the DSL signal. If the data transmission is still audible, using two DSL filters, daisychained in series, should eliminate the problem. The RJ11 female port provided on the filter case simply connects the DSL router directly to the phone line (most DSL filters have a socket marked DSL or ADSL that just connects the DSL line pair directly through to the incoming phone line pair via the BT plug, without any filtering or processing of any kind). The ringer wire is unnecessary in unfiltered parts of the wiring and its removal can often improve performance and reliability of the broadband service. This is due to the unbalancing effect that the ringer wire (on long extensions) can have on the matched twisted pair. Thus reducing the signal to noise ratio and also the high frequency response of the subscriber line. When ADSL was first introduced in the UK it was installed by a technician who replaced the front part of the NTE5 (if the property still had an old style master socket it would be replaced with an NTE5) with one containing a filter. Any hardwired phone extensions were disconnected from the original front part and connected to filtered terminals on the back of the filter. The DSL modem (which at the time was also BT supplied) and, if present, a phone or plug-in extension, could then