Summary: | ASTERISK-05213: Getting the clocking right for E1 and T1 lines | ||
Reporter: | steveu (steveu) | Labels: | |
Date Opened: | 2005-10-02 03:42:33 | Date Closed: | 2008-06-07 11:05:12 |
Priority: | Major | Regression? | No |
Status: | Closed/Complete | Components: | Core/General |
Versions: | Frequency of Occurrence | ||
Related Issues: | |||
Environment: | Attachments: | ( 0) zaptel.conf.sample.patch | |
Description: | If the wording about setting clock sources in zaptel.conf.sample is changed to that below I think I will have a lot less support issues with spandsp. :-) This was discussed some time ago on the mailing list, but it looks like CVS was never changed. I think the *majority* of users currently have their clock sources set incorrectly, and the current wording makes the adamant they are right. # span=<span num>,<timing source>,<line build out (LBO)>,<framing>,<coding>[,yellow] # # All T1/E1 spans generate a clock signal on their transmit side. The # <timing source> parameter determines whether the clock signal from the far # end of the T1/E1 is used as the master source of clock timing. If it is, our # own clock will synchronise to it. T1/E1's connected directly or indirectly to # a PSTN provider (telco) should generally be the first choice to sync to. The # PSTN will never be a slave to you. You must be a slave to it. # # Chose 1 to make the equipment at the far end of the E1/T1 link the preferred # source of the master clock. Chose 2 to make it the second choice for the master # clock, if the first choice port fails (the far end dies, a cable breaks, or # whatever). Chose 3 to make a port the third choice, and so on. If you have, say, # 2 ports connected to the PSTN, mark those as 1 and 2. The number used for each # port should be different. # # If you choose 0, the port will never be used as a source of timing. This is # appropriate when you know the far end should awlways be a slave to you. If the # port is connected to a channel bank, for example, you should always be its # master. Any number of ports can be marked as 0. # # Incorrect timing sync may cause clicks/noise in the audio, poor quality or failed # faxes, unreliable modem operation, and is a general all round bad thing. | ||
Comments: | By: Jared Smith (jsmith) 2005-10-02 08:54:20 Personally, I think this is a great idea. I see people misinterpret the timing all the time, and the timing set to 0 on all their spans. By: Olle Johansson (oej) 2005-10-02 15:08:35 Please provide a patch for the sample config file. By: steveu (steveu) 2005-10-02 18:48:45 I have uploaded the same change as a patch file. By: Russell Bryant (russell) 2005-10-04 15:03:23 Very nice. I think it's very informative, and will probably reduce the number of problems Digium support has with these issues as well. It looks like there might be a few typos, though. In the second paragraph, did you mean for "Chose" to be "Choose" ? By: Russell Bryant (russell) 2005-10-04 15:05:29 Oh, and in the 3rd paragraph, "awlways" --> "always". By: Kevin P. Fleming (kpfleming) 2005-10-04 18:52:09 Committed to CVS HEAD, thanks! By: Digium Subversion (svnbot) 2008-06-07 11:05:12 Repository: dahdi Revision: 790 U trunk/zaptel.conf.sample ------------------------------------------------------------------------ r790 | kpfleming | 2008-06-07 11:05:08 -0500 (Sat, 07 Jun 2008) | 2 lines make timing source configuration easier to understand (issue ASTERISK-5213) ------------------------------------------------------------------------ http://svn.digium.com/view/dahdi?view=rev&revision=790 |