# Re: NZ phone line impedance

Discussion in 'NZ Computing' started by Peter KERR, Jul 17, 2003.

1. ### Peter KERRGuest

In article <bf68fe\$bblgo\$-berlin.de>,
(Peter Gutmann) wrote:
>
> For some unknown reason some people I know want to bring some flashy Phones
> with Everything over here from Germany to use (I guess the built-in foot
> massager and coffee maker is something they can't do without). Apparently
> European lines are 270 ohm + 750 ohm/150nF complex impedance, from memory NZ
> has straight 600 ohm lines. Does anyone know of any potential issues with
> this?
>

That German figure sounds like a typical phone line impedance,
except it should be specified a bit more rigorously than that.
ie. Z = R + jX
your figure is R + Zc, where I assume the 150nF capacitance is
across the line, and the 750 ohms in series with the line. This
would normally be, but you have not stated, inductive.

NZ lines can no way be 600 ohms resistive with no phase angle.
P'raps get hold of an impedance bridge and check a line:
preferably one as far from the exchange as you can find,
disconnect all phones, modems etc, and think of a way to deal with
the 50 volts DC injected at the other end...

Peter KERR, Jul 17, 2003

2. ### colincoGuest

In article <>, Peter KERR
wrote...
> In article <bf68fe\$bblgo\$-berlin.de>,
> (Peter Gutmann) wrote:
> >
> > For some unknown reason some people I know want to bring some flashy Phones
> > with Everything over here from Germany to use (I guess the built-in foot
> > massager and coffee maker is something they can't do without). Apparently
> > European lines are 270 ohm + 750 ohm/150nF complex impedance, from memory NZ
> > has straight 600 ohm lines. Does anyone know of any potential issues with
> > this?
> >

>
> That German figure sounds like a typical phone line impedance,
> except it should be specified a bit more rigorously than that.
> ie. Z = R + jX

snipped

The german figures refer to a representative termination model 270R in
series with parallel 750R,150nF.
NZ equiv borrowed from UK is 370R + //620R,310nF

If you want to know more http://www.telepermit.co.nz/TNA102.pdf

colinco, Jul 17, 2003

3. ### MutleyGuest

Peter KERR <> wrote:

>In article <bf68fe\$bblgo\$-berlin.de>,
> (Peter Gutmann) wrote:
>>
>> For some unknown reason some people I know want to bring some flashy Phones
>> with Everything over here from Germany to use (I guess the built-in foot
>> massager and coffee maker is something they can't do without). Apparently
>> European lines are 270 ohm + 750 ohm/150nF complex impedance, from memory NZ
>> has straight 600 ohm lines. Does anyone know of any potential issues with
>> this?
>>

>
>That German figure sounds like a typical phone line impedance,
>except it should be specified a bit more rigorously than that.
>ie. Z = R + jX
>your figure is R + Zc, where I assume the 150nF capacitance is
>across the line, and the 750 ohms in series with the line. This
>would normally be, but you have not stated, inductive.
>
>NZ lines can no way be 600 ohms resistive with no phase angle.
>P'raps get hold of an impedance bridge and check a line:
>preferably one as far from the exchange as you can find,
>disconnect all phones, modems etc, and think of a way to deal with
>the 50 volts DC injected at the other end...

Try here.

http://www.telepermit.co.nz/TNA102.pdf

http://www.telepermit.co.nz/TNA 151.pdf

Or for the index.

http://www.telepermit.co.nz/PtcSpecs.html

The NZ trans plan is now very close to Australia

Mutley, Jul 18, 2003