Odd telephone fault

[Wibble]

Secomded! Advantage is we can make internal calls between extns etc

[dennis]

I order via a pharmacy to order, collect, and dispense the meds. It gives them the hassle of dealing with what are becoming PIA doctors surgeries.

You may want to avoid some of the larger chains like boots who can only submit and collect stuff on Tuesday (in my case) and use a smaller more accommodating one.

[dennis]

Usual tony non response. Introduces something irrelevant to score points and then declines to explain it.

[polygonum]

I will not submit to a pharmacy controlling my medicine. For example, people can have great difficulty in getting specific products via particular pharmacies. Maybe the pharmacy (as in the case of Boots or Lloyds) likes to dispense its own packaged version (e.g. Almus or Lloyds). Or maybe they will refuse to leave product in its original packaging instead transferring the contents into their own child-proof containers - and omitting batch number and use by date.

If ever there is a shortage, I want to be able to get my supply from any pharmacy in the country, bricks and mortar or on-line, which is able to supply and not be stuffed from the outset. Same applies if I simply decide to go elsewhere for my convenience.

I also regularly see my mother's medicines not being supplied in time. E.g. a four-week supply arriving in the evening after the last dose has been used. They are utterly incompetent at delivering on their promises.

[GMM]

Sounds like a weird fault but anything is possible of course! I would start by taking one of two routes: The first would be accost an Openreach man next time you see one in the street. I've always found them extremely helpful and easy going. The second would be to try the BT forums. From what I have seen, they monitor these, so will pick up issues and recommend ways forward. This might well attract their attention(!)

[Geoff Pearson]

I am very grateful to everyone - reassuring that there are so many theories which I will explore. I am reasonably technically competent, licensed radio amateur (G8) and degree in physics and I still can't believe the fault I can see for myself. I will rig some temporary test extension wiring before I descend below to install it properly. My Cat5 has plenty of spare capacity so I can avoid my old system. I will let you know when I succeed.

[tony sayer]

Humm .. seems as if it ought to work OK..

Why don't they implement it ?..

[tony sayer]

No Den, not irrelevant at all. A way that VoIP telephony works that might help you to understand some aspects of its system of operations...

[Bob Eager]

They have for our local GP group and pharmacy. I don't use that one though.

[Bob Eager]

Not sure if this has been covered in this rather long thread...

Can you get a phone that can be switched to loop disconnect dialling? Then try dialling that number. If that works, it has to be a tone filtering problem.

[dennis]

Go on explain it. Or don't you think you can.

[Geoff Pearson]

will do.

[tony sayer]

In a nutshell .. without boring the arse off other contributors..

Don't confuse it with the Vocoder thats used in the musical instrument sense. Its a Codec thats tuned to the human voice in a particular way it can in some variants digitise speech and use Analysis/synthesis coding and represent that as a speech sound all of which is used to conserve bandwidth which is the ultimate aim of most any coder.

G.723.1 is mostly used in Voice over IP (VoIP) applications due to its low bandwidth requirement. Music or tones such as DTMF or Fax tones cannot be transported reliably with this codec, and thus some other method such as G.711 or out-of-band methods should be used to transport these signals...

You'll find that if you have some types of VoIP units that we have which are made by Messers Multitech on the states these can provision 2 and 4 wire private Point to Point speech band circuits over IP . Try sending music or tones down them as corporal Jones would say "they don't like it up 'em"

You'll find out more at the description of this type of codec at the ITU website..

A part of which is here..

This coder was optimized to represent speech with a high quality at the above rates using a limited amount of complexity. It encodes speech or other audio signals in frames using linear predictive analysis-by-synthesis coding. The excitation signal for the high ratecoder is Multipulse Maximum Likelihood Quantization (MP-MLQ) and for the low rate coder is Algebraic-Code-Excited Linear-Prediction (ACELP). The frame size is 30 msand there is an additional look ahead of 7.5 ms, resulting in a total algorithmic delay of 37.5 ms. All additional delays in this coder are due to processing delays of the implementation, transmission delays in the communication link and buffering delays of the multiplexing protocol.

The description of this Recommendation is made in terms of bit-exact, fixed-point mathematical operations. The ANSI C code indicated in clause 5 constitutes an integral part of this Recommendation and shall take precedence over the mathematical descriptions in this text if discrepancies are found. A non-exhaustive set of test sequences which can be used in conjunction with the C code are available in the electronic attachment.

[dennis]

That is exactly what I said, but in English.

However G.723.1 is not a vocoder it is an ITU *CODEC*.

So I am still waiting for you to come up with something relevant and new.?

PS the main problem with fax isn't the transport of the tones as it can still fail with a G.711 64k CODEC. I will leave you to ponder why.

[The Other Mike]

A situation that is repeatable for almost all number ranges across the UK with one or two exceptions

[Bob Eager]

My number begins with a 6!

It's 01227 6xxxxx

(but it is VoIP)

[Vir Campestris]

I haven't received a fax since... Friday. Well, not me directly, it was between solicitors. I've used it to fax signed documents quite recently.

Andy

[The Other Mike]

What I meant was that for most numbers ranges within each specific STD code area, there are a number of initial digits that are deliberately not allocated so the exchange will stop sending dial tone, should return number unobtainable, but could do 'something else'

The exceptions being areas where all initial first digits are allocated and all number dialling for local calls is required, as in the 01202 area.

[tony sayer]

Then you shouldn't be in need of being told again then Den..

Yes!, but the Vocoder part is the crucial element in understanding this. Its the part thats using analysis synthesis coding and is the reason why it won't cope with tones or fax that well if at all..

For your erudition the G.711 codec is a 64K PCM one and does handle FAX and voice and discrete tones very well over switched network infrastructure. However over IP circuits the jitter may be unacceptably high hence the T.38 implementation to carry that.

The original point is that Vocoder types don't carry fax because of the way they operate..

Does anyone apart from Medical and soliciting persons still use Fax anymore?..

[dennis]

Maybe thats why I called it a G711 64K codec?

It had better do so as its what the public network uses (well the mu law variant IIRC).

Spoilsport, now tim will know where to look. Do you want to tell him what actually happens with a FAX over a proper VoIP system?

(PS I did actually have reliable FAX over VoIP many years ago, before T38 was done, but not over the Internet as that is just too variable for it to be reliable.)

the original point was that VoIP is so bad quality wise that it can't handle tones. Nothing was said about vocoders at all until tim decided to introduce them and then not explain why.

They are still irrelevant as there are many codecs used and many have nothing to do with vocoders at all.