At 2002-09-16 00:18 -0800, Elbert Smit wrote: >I have some troubles with a modem connection and can't find some important >information. Maybe someone on this list can help. > >I'm looking for the maximum signalstrength (transmitlevel) that a modem may >use to send its data. I tried to find this value by asking KPN business >(Dutch telecom), but did not get any usable answer. > >I also would like to know the position of the guardtone in the >frequencyspectrum according to the Dutch regulations. V22bis standard states >that it is a national option. Possible options are: 550Hz, 1800Hz, none. >Signal strength is also interesting.
When I was still working on modem-like equipment KPN had very elaborate books about all these matters. They weren't cheap. Somewhere between 100 and 200 euro I think. Perhaps you should try to get one of those. I just found the book back. It's called: - Beschrijving Interface Netwerkaansluiting: Telefoonnet van PTT Telecom - Uitgave: mei 1991 - Netwerkbedrijf van PTT Telecom - NLNR 99.7953 - 99-7953/09-91 You could try calling: 050-5222263 or 06-0401 (perhaps that's now: 0906-0401?). In any case, you shouldn't contact a commercial department, but a technical department. Perhaps you could also figure out the maximum level by studying the ISDN PCM norm, of which the A-Law version is used in Europe. Consider that 56kbit/s modems use the 65536 voltage levels of the signal to code their data. We used to detect call-progress states by counting the number of times that a signal went through the zero-level, which is quite easy to detect without having to input and analyze the signal through an ADC. I should still have the source code. I could also make scans of parts of the book if you like. Greetings, Jaap -- Author: Jaap van Ganswijk INET: [EMAIL PROTECTED] Fat City Network Services -- 858-538-5051 http://www.fatcity.com San Diego, California -- Mailing list and web hosting services --------------------------------------------------------------------- To REMOVE yourself from this mailing list, send an E-Mail message to: [EMAIL PROTECTED] (note EXACT spelling of 'ListGuru') and in the message BODY, include a line containing: UNSUB CHIPDIR-L (or the name of mailing list you want to be removed from). You may also send the HELP command for other information (like subscribing).
