> > What is in the bug tracker helps make things clearer to people who know > > what they are doing. What we need is something that makes things clear > > to laymen. Saying internally and externally clocked doesn't cut it. It > > needs to be made clear to laymen that clocking internally is rarely > > right; that slaving to a PBX, when there is also a PSTN connection is > > almost never right; that the PSTN is the grand master of the telecoms > > universe, and all Asterisk boxes should be its slave. > > > > Maybe the confusion is because some pieces of the explanation are being > left out. If you look at the leads on a synchronous RS232 interface it > is very clear: Rx clock and Tx clock, and people understand that. It's > not as clear-cut with T1/E1. > > I'm not the person to explain this, but someone (Rich Adamson perhaps, > or a Digium engineer) needs to explain phase-locked loops and the > recovery of the timing signal from the data stream. Perhaps > understanding that the timing comes from the data stream itself might > lead to better understanding.
How about this... Replace the old text in /usr/src/zaptel/zaptel.conf.sample: # span=<span num>,<timing>,<line build out (LBO)>,<framing>,<coding>[,yellow] # # The timing parameter determines the selection of primary, secondary, and # so on sync sources. If this span should be considered a primary sync # source, then give it a value of "1". For a secondary, use "2", and so on. # To not use this as a sync source, just use "0" with this text: # span=<span num>,<timing>,<line build out (LBO)>,<framing>,<coding>[,yellow] # # All T1/E1 spans generate a clocking signal on the transmit side. The # timing parameter determines whether the clocking signal from the opposite # end of the T1/E1 is used to sync our clock. For T1/E1's connected to a # pstn provider (telco), chose 1 for using this T1 as the primary clock, # 2 for a secondary (if multiple T1/E1's are in use and the second T1 is # to be used for clock sync should the primary fail), or 3 for the next # T1, etc. If the T1/E1 is connected to a channel bank or if the T1/E1 # is not to be used for clock sync, then specify the timing as 0. (A quad # T1/E1 card should only have a single T1/E1 specified as timing = 1, or # primary clock sync. Incorrect timing sync may cause clicks/noise in # the audio, poor quality faxes, or fax failures, etc.) If this is helpful, I'll submit a bug for the text. Thoughts anyone? Rich _______________________________________________ Asterisk-Users mailing list Asterisk-Users@lists.digium.com http://lists.digium.com/mailman/listinfo/asterisk-users To UNSUBSCRIBE or update options visit: http://lists.digium.com/mailman/listinfo/asterisk-users