Re: Commodore Modems - C1660 and C1670

From: Groepaz (
Date: 2004-01-28 11:08:19

On Wednesday 28 January 2004 06:25, William Levak wrote:
> >Hi All,
> >
> >I've received a few of these and before plugging into the Australian
> >telephone system - and having Telstra issue me a bill for $$$$ damages -
> >I was wondering how universal these modems were. Was the modem different
> >for different markets? The ones I have came from the USA.
> As far as I know, telephones everywhere are very much the same, with some
> slight timing differences.
> In North America, the dial pulse is +90 V, and the voice signal is -48 V
> at 21 to 35 mA.  You should be able to measure these with a volt meter.

wow 48v ? that sounds a bit much :) afaik its ~60ac for letting the phone
ring, but its ~12vdc for voice...
(sorry this is german, but very entertaining to read nevertheless :=P)

"im Leerlauf liegt auf den Rufleitungen eine Spannung von ca 60 Volt an - 
sobald abgehoben wird, bricht diese Spannung allerdings sinnlos zusammen 
und krebst hinford und heropel so in der Gegend von mickrigen 10 bis 
15 Volt rum."

this is certainly true for germany, and since i have used american and
australian phones/modems/faxes/other toys on german phonelines myself
with no problem, its probably simelar in the rest of the world.

a more important difference seems to be different pinouts of the TEA
plugs, german "bundespost" came up with their own version here :)


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