Hello Jaap & others, > 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
There has been a follow-up on this book. KPN has put these specifications as pdf-files on the web. You can download them from the following site if you are interested: http://www.kpn.com/br2/ng/catalog/cat_Browser.jsp?c=ok&contentOID=39541&site =0&channel=1 The current versions do not answer the questions about the maximum transmit level and the guard tone. When I just searched for the link I found out that KPN has put new documents on the web. There is a contact reference for questions about the PSTN specification at the first page of the document. I've just sent the questions to this email address. Hopefully will this result in some usable answers. > 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. Are these phonenumbers of technical departments? > 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've used a laptop with soundcard and a high impedance connection to the phonelines to record the modem connections. If you use a sound-edit program like Cooledit2000 with a spectral view, you can see DTMF-tones, calling tones, answer tones, measure tone lengths, frequencies, etc. I got this tip from a KPN-technician. Very nice and cheap tool, when you already have a laptop of course ;-) So far, it gave a lot of information about the connections and solved some problems, but not all. > I could also make scans of parts of the book if > you like. I think the pdf-files are more uptodate, but I appreciate your help, thanks! Elbert Smit. -- Author: Elbert Smit 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).
