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Old 29th Oct 2017, 4:28 am   #12
julie_m
Dekatron
 
Join Date: May 2008
Location: Derby, UK.
Posts: 7,735
Default Re: Help needed with bits!

I had one like that too, with the whole house wiring already filtered and a 1.8μF ringing capacitor on the "clean" side for the full REN of 4. This took the form of a replacememt faceplate for the existing NTE5 master socket, with the filtering components and RJ-11 and RJ-431 sockets; plus a row of Krone terminals carrying the filtered voice, ringing and common return and also the unfiltered line to allow an extension cable to be run to an RJ-11 socket for the modem / router.

When I got FTTC (Fibre To The Cabinet, a.k.a VDSL -- Very short, Digital Subscriber Line; the length of cable carrying voice and data combined, which is the most susceptible to interference which is the factor having the greatest limiting effect on data rate, is very short) they replaced my modified NTE5 with a new NTE5D; this is a three-tier affair, which already includes whole-house filtering and separate sets of Krone terminals for voice (on the front faceplate) and data (on the middle layer, which also has an RJ-11 connector for the VDSL modem / router) extension wiring. And two internal test sockets; one with filtered voice and ringing on the middle layer, and one with the unfiltered line on the back box.

It's perhaps unfortunate that the decision was taken historically to fit a single capacitor to separate the voice and ringing signals inside the Network Terminating Equipment and then requiring three-or-more core extension wiring or microfilters with a capacitor that only support an REN, rather than rely on a separate capacitor in each phone, requiring just two cores and allowing any microfilter to be used as a whole-house filter; but at that time, nobody ever envisaged trying to pass radio-frequency signals along copper wiring meant only for voice signals up to 4kHz. And it was very effective at its designed purpose of preventing other extensions from "tinkling" when dialling-out using Loop Disconnect (pulse) signalling.

When we get fibre to the premises, we won't be needing those filters anymore, and could return to pre-broadband voice wiring practices; but DTMF (tone) dialling is inherently tinkle-free anyway, since it does not create hefty current pulses by intertupting the line. But a whole house full of DECT phones needs only one comnection to the line anyway; and in any case we might end up with a VoIP (Voice over Internet Protocol) Analogue Telephone Adaptor as part of the Subscribers' Premises Equipment acting as virtual Network Terrminating Equipment for a locally-emulated exchange line, and send voice calls directly over the Internet as SIP traffic. Or we might have all SIP phones throughout the home, and a PABX in the SPE. Or SIP clients in out mobile phones, able to route calls via the Internet wherever a suitable connection was available -- possibly even switching from SIP to GSM to DECT as seamlessly as switching from WiFi to cellular data

It's telephony, Jim, but not as we know it .....
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