Hello Marcel,
On Wed, 08 Apr 2009 19:14:36 +0200, "Marcel Klein" marcel@koeln.ccc.de wrote:
Hm wouldn't it be possible to sync our clock with the official networks (without an extra ISDN-line)? Somebody told me that there are several ways to sync the clock. Here we discussed the ISDN way, but somebody told me that it should also be possible to set the clock over GPS and/or other networks in our area.
The BS-11 takes the clock from the E1 line as reference. So you somehow have to make sure that this clock is stable and accurate. If you don't use another ISDN line, you have to generate a stable and accurate clock for the E1 card yourself.
Another approach might be to calibrate the BS-11 internal oscillator, this can be done by software. However it is not yet sure if this will solve the problem in a reliable way, also I have not yet found a way to measure the BS-11 clock without opening the case.
If you want to experiment with your test network only it should not care, beside some additional effort to initially register to the network, the BS-11 clock is most certainly stable enough so that a phone can stay synchronized to the BS-11 network and that it can be used with this network.
Best regards, Dieter
On Wed, Apr 08, 2009 at 07:44:02PM +0200, Dieter Spaar wrote:
The BS-11 takes the clock from the E1 line as reference. So you somehow have to make sure that this clock is stable and accurate. If you don't use another ISDN line, you have to generate a stable and accurate clock for the E1 card yourself.
Dieter, what I just found out is that the LI object has a user-configurable setting, where we can force it to be stand alone or locked to the E1.
We could add this setting to the bs11_config program so people can try if their E1 clock or their [10 years uncalibrated] BS11 internal oscillator is better.
What do you think?
Another approach might be to calibrate the BS-11 internal oscillator, this can be done by software. However it is not yet sure if this will solve the problem in a reliable way, also I have not yet found a way to measure the BS-11 clock without opening the case.
I'm quite sure there must be an option to do this externally. The internal oscillator must be calibrated every two years, and I'm sure they do this without opening the case (in the field...)
Regards,
-
Dieter Spaar -
Harald Welte