Getting matching transformer from telephone

[Phil Allison]

"Salmon Egg"

I know of no situation where something specified as say a 150 ohms
1-to-1 matching transformer would perform significantly different than
something specified as a 600 ohms 1-to-1 matching transformer. This
assumes that they both can support the same voltage over the same
(telephone audio) bandwidth. Am I missing something?

** Errr - yep.

Impedance ratings matter very much in relation to the drive and load
impedances that are bests for a particular transformer.

Get them wrong like that and the overall frequency response will not be flat
across the audio band.



....... Phil

 

[Eeyore]

An ignorant statement, to say the least.

As far as it being a matching transformer, the line
impedance varies typically from perhaps 100 Ohms all the
way up to perhaps 2000 Ohms... but you will not find
anything in a telset to adjust it to match. That's because
nobody cares if it is even close to matching the line
impedance.

So you agree it's NOT a matching transformer you TWAT ?

You won't find pointless transformers (dead weight) in WORLD telecoms.

Graham

 

[Eeyore]

and the equipment he designed is for sale on Ebay.

IT IS

 

[Eeyore]

Which is why I stated its primary purpose as being that of isolation

What exactly needs isolating from what ? Have you noticed they tend to be
made of plastic ?

Graham

 

[Eeyore]

I know of no situation where something specified as say a 150 ohms
1-to-1 matching transformer would perform significantly different than
something specified as a 600 ohms 1-to-1 matching transformer. This
assumes that they both can support the same voltage over the same
(telephone audio) bandwidth. Am I missing something?

Twisted pair cable as used for telecoms has a nominal 100-110 ohm
inpedance. See the ADSL specs.

600 ohms is an irrelevant historical nonsense from the days when they used
telegraph wires for phone circuits.

Graham

 

[krw]

IT IS

You forgot; "A place that would shame Ali-baba & his 40 thieves",
Dumb Donkey.

 

[Phil Allison]

"Floyd Lunatic Davidson"

Eeysore

The transformers are made of plastic???

** Don't be such a pompous bloody prick.

Of course he meant the phone itself.

A telephone loop has both VF (voice frequency) and DC
signals going in both directions, all of which need to
be "isolated" from each other.

** Don't be such a pompous bloody prick !!

Any "isolation " transformer has " galvanic isolation" .

Look it up on Google, if you are still completely clueless.

Wot a Wanker.



..... Phil

 

[Bill Janssen]

Salmon Egg wrote:



Twisted pair cable as used for telecoms has a nominal 100-110 ohm
inpedance. See the ADSL specs.

600 ohms is an irrelevant historical nonsense from the days when they used
telegraph wires for phone circuits.

Graham

Impedance for an un-loaded pair varies with frequency. So at DSL
frequencies the impedance
is 100 to 110 Ohms. But for telephone use They preferred to use loaded
pairs and they were
designed to be 900 Ohms. And the phone should be a reasonable match to
the line to minimize refections which bother the users as echoes

The transformers in some sets was not an isolation transformer but a
hybrid and matching transformer. The carbon mic. used in the old phones
was powered from the line. And many
of the newer phones derive power from the line. So isolation can't be used.

Bill K7NOM

 

[Phil Allison]

"Floyd Lunatic. Davidson"

"Phil Allison

I'm sorry, but the nickname your mother uses for you is
not appropriate in reference to other people.

Please not that I have not said it is a matching
transformer, nor have I said that it is necessarily
appropriate for the OP. All I did was properly describe
what it actually is.

** You failed to even do that.

Wrong again. It provides isolation. As I mentioned in
another post, a POTS loop needs to isolate the VF signal
from the DC signal, and also to isolate the transmit
signal from the receive signal.

** Listen you fucking dickwad !!

The term " isolation transformer " has a specific meaning in electronics and
electrical work = "galvanic isolation".

You clearly have no bloody clue about the topic.

Piss off.



....... Phil

 

[Phil Allison]

"Bill Janssen"

Impedance for an un-loaded pair varies with frequency. So at DSL
frequencies the impedance
is 100 to 110 Ohms. But for telephone use They preferred to use loaded
pairs and they were
designed to be 900 Ohms. And the phone should be a reasonable match to the
line to minimize refections which bother the users as echoes

** Huh ??

Audible echoes on a few miles of twisted pair ???

The speed of electrical signals must be a * hell of a lot * slower than C
where you live - pal.

The transformers in some sets was not an isolation transformer but a
hybrid and matching transformer. The carbon mic. used in the old phones
was powered from the line. And many
of the newer phones derive power from the line. So isolation can't be
used.

** At least you do know what an "isolation " transformer is.

Unlike some here.


...... Phil

 

[Phil Allison]

"Floyd Lunatic Davidson"
Eeysore

That would be sort of stupid, eh?

** YOU are the only STUPID thing here - pal.

What the phone is
made of is not important in any way to this
conversation.

** ASSHOLES like you do not get to decide what is relevant.

The fact that phones are made of plastic IS the damn reason that GALVANIC
isolation from the phone line is not required.

Don't much care for anyone who knows what they are
saying, eh?

** God almighty - you are one arrogant fucking cunthead.

Er, Phil...

** Go get fucked

- you INSANE PRICK !!!

If you are only aware of one possible use for an
"isolation" transformer,

** Go get totally fucked

- you INSANE AUTISTIC PRICK !!!



....... Phil

 

[Salmon Egg]

A telephone loop has both VF (voice frequency) and DC
signals going in both directions, all of which need to
be "isolated" from each other. The transmit and receive
VF signals also have to be isolated from each other
(which is why the transformer is commonly called a
"Hybrid Network").

For a long time I believe the term actually used for this transformer
was "induction coil."

Bill

 

[Salmon Egg]

** Go get fucked

- you INSANE PRICK !!!





** Go get totally fucked

- you INSANE AUTISTIC PRICK !!!



...... Phil

Phil, have you passed the age of adolescence?

Bill

 

[Phil Allison]

"Salmon Egg"


** Piss off - you fuckwitted BAD EGG !!

And take all your STINKING AUTISTIC PRICK scumbags with you.



... ... Phil

 

[Phil Allison]

"Lostgallifreyan"


** **** OFF -

YOU RIDICULOUS DICKWAD !!

 

[krw]

Now, you are catching on. Eeyore is a british idiot, and Phil is a
mentally ill Aussie who won't take his medication.

Not much of a difference, eh?

 

[Phil Allison]

"Lostgallifreyan"


** **** OFF -

YOU RIDICULOUS LYING DICKWAD !!

 

[Phil Allison]

"Lostgallifreyan"

"Phil Allison"

Posted after last post in a subthread does not mean aimed at last poser,
when
the new post is a useful read for all posting. Got that? Read it, it's a
lot
more interesting than you are right now.

** Oxygen thieves like this anencephalic turd need shooting.




.... Phil

 

[Phil Allison]

"Floyd LUNATIC AUTISTIC Davidson"

"Phil Allison"

That is not true.

** Fraid it damn well is - FUCKHEAD.

You need to use Google and learn something.

** You are nothing but a FUCKING LIAR !!

http://en.wikipedia.org/wiki/Isolation_transformer

http://www.leonaudio.com.au/line_iso.htm


**** off - you goddamn, code scribbling FREAKOID !!!




...... Phil

 

[Phil Allison]

Floyd Lunatic ASSHOLE Davidson"

That would be sort of stupid, eh?

** YOU are the only STUPID thing here - pal.

What the phone is made of is not important in any way to this
conversation.

** ASSHOLES like you do not get to decide what is relevant.

The fact that phones are made of plastic IS the damn reason that GALVANIC
isolation from the phone line is not required.

Don't much care for anyone who knows what they are
saying, eh?

** God almighty -

you are one arrogant fucking NUT CASE cunthead !!




** Go get totally fucked

- you INSANE AUTISTIC PRICK !!!



....... Phil