After that you should have the same framing on both sides - with or without CRC4. And, finally, you should configure either side of the link to take clocking from the other party.
I have a similar case
Alcatel OmniPCX with S2M E1 Card
Asterisk installed on Debian
Digium wildcard TE205P
Teh PBX is configured as slave and the card is master for the clock
And I am getting RED alarm on the span port
Can anyone using the same setup share with me his/her zaptel.conf, zapata.conf and the parameters used in the OmniPCX?
thanks in advance