Konrad, Thank you for the response. Your insights to Swiss billing tones has generated some questions: If the billing tones can be disabled is it possible for modems and fax machines to pass Swiss approvals sans filters. If so what are the requirements to do so?
Thank you in advance. Amities, Duane _______________________________________ On Wed, 26 Mar 1997, Konrad Gysi wrote: > Dear Duane, Ben, Rene.... > > Switzerland have the metering tones (12 kHz) enabled on all the lines by > default. But you can ask for disabling it when ever you want. > > best regards konrad, swisscom (new name for telecomm PTT switzerland) > > > >Dear Duane and Ben, > > > >It is indeed possible to have a modem approved without filters in them. > >They don't even check whether you remain connected, only whether > >your impedance isn't too low at 16KHz. It is unclear to me how well > >a modem would perform without it. The ones that had no filter but were > >used for demos worked pretty well with V.42 switched on. > >A difference between Germany and for instance Switzerland is that > >in Germany the metering tones are enabled by default on all lines, > >one has to request them to be disabled. Switzerland, as far as I know > >doesn't have them enabled on all the lines by default. > > > >Best regards, Rene > > > >---------- > >From: [email protected] on behalf of Duane J Marcroft > >Sent: Tuesday, March 25, 1997 3:31 AM > >To: [email protected] > >Cc: [email protected] > >Subject: Re: Filter for Germany > > > >Ben, > > > >I have designed a number of PCMCIA cards in the last several years and > >none them have billing tone filters for Germany. I believe it is now > >possible to have a modem approved in Germany sans filters. The modem is > >now allowed to make some errors in the presence of metering tones, but it > >must not drop the line. Also, if you use the inductance of the > >transformer in the correct way it is possible to increase the Rockwell > >modem tolerance of metering tones beyond 0.7 vrms and in the majority of > >connections the modem will not hiccup. By adjusting modem firmware it is > >possible to bridge hiccup periods and not disconnect. > > > >Regards,................. > > >
