Re: Getting matching transformer from telephone

[Eeyore]

:
:A proper 600:600 transformer will be more expensive than a 10k:10k one too.
:
That may be true but how many readily available 10K:10K audio transformers have
a 3.5Kv isolation rating?

I believe this was required IIRC for only brief use. He could avoid using it during
thunderstorms too.
http://uk.farnell.com/triad-magnetics/ty-141p/transformer-audio-0-1w/dp/1610409
Probably in stock at Newark

Graham

 

[Eeyore]

I believe this was required IIRC for only brief use. He could avoid using it during
thunderstorms too.
http://uk.farnell.com/triad-magnetics/ty-141p/transformer-audio-0-1w/dp/1610409
Probably in stock at Newark

http://www.farnell.com/datasheets/120167.pdf

Data sheet implies may be suitable for telephone coupling.

Graham

 

[Jamie]

Ross Herbert wrote:




I believe this was required IIRC for only brief use. He could avoid using it during
thunderstorms too.

Why? That takes the fun out of it!


http://webpages.charter.net/jamie_5"

 

[tony sayer]

What do you suppose happens to the bandwidth of a signal as it
is passed through successive audio devices that are band
limited to 300-3400 Hz?

Would you expect to get 300-3400Hz +- ndB response in an end
to end loopback test when you use white noise as the test
signal? (n =ITU spec)

Going from a handset to a PBX to MUX to a CO into the network
and back if each device has a 300-3400Hz response the looped
back signal should be more band limited than the first device
in the signal chain with 300-3400Hz response originating test
signal by quite some bit.


Peace
dawg

Well either over long or local circuits -some- level reference needs be
quoted .....

 

[tony sayer]

In the context presented, that is generally true... but
I'd like to point out that the shielding on multipair
telephone cables is 1) grounded, 2) commonly conducts
current, and 3) the noise reduction provided is
*enhanced* by the current!

Both ends of the cable are well grounded and any induced
current in the shield will be greater than in any
individual cable pair. The current in the shield
induces an opposite current into the cable pair, thus
reducing the total noise signal in each pair.

Do you manage to get grounds in that soil over there, seemed to think it
was more permafrost..

Those pix on the Floyd website look rather, well "cool" ...