asterisk users - Oct 2006 - Do you encounter this REC alarm before?

We deployed a PABX in China, orginally it used Netcom????'s E1, the
zaptel.conf is as following:


span=1,0,0,ccs,hdb3,crc4
bchan=1-15
bchan=17-31
dchan=16
loadzone=cn
defaultzone=cn

However, recently customer changed to use China Telecom??????'s E1, it
always show REC, RED/REC, RED,  cycling alarm when I run zttool in
console. They sometimes still can make call, but the quality was quite
bad. China Telecom's engineers already checked the cable using some E1
test tools, it works perfect, and they even plug E1 into a Panasonic
PABX, it didn't have any quality problem. FYI, The card model is
TE412P.

-- 
Regards!
Liangliang