[Asterisk-Users] BRIstuff - synchronization with PSTN?

[Niksa Baldun]

Hello,

for a long time I've been having problems with analog modems and faxes
communicationg over ISDN BRI lines. Now I began to suspect that this is
due to * being out of sync with the PSTN. I have a quadBRI card with
first two ports connected to PSTN, and defined as follows:

span=1,1,0,ccs,ami
span=2,2,0,ccs,ami

This should mean that spans 1 and 2 are used as primary and secondary
synchronization sources. However, when I check the spans with zttool it
says:

Sync source: Internally clocked

Does this mean that ISDN interface is not synchronized with the PSTN? If
so, why, and how can I correct it?

Thanks