The problem was someone upgraded rpm , modules and hence messing up the DAHDI settings.
Server --> Dell
ISDN Card -- > TE110P
Service Provider -- > Singtel ISDN-30
Software used --> AsteriskNow
Asterisk Core --> asterisk-core-1.6.2.24-1_centos5
GUI -- > Freepbx
these are the DAHDI settings (Freepbx)
Framing/Coding : CCS/HDB3/CRC4
Signalling: PRI-CPE
SwitchType: EuroISDN
Sync/Clock Source: 0
Context: from-pstn
*Others that are not mention , leave it as default
For the hardcore users,
# cat /etc/dahdi/system.conf
span=1,0,0,CCS,HDB3,CRC4
bchan=1-15,17-30
dchan=16
loadzone=sg
# cat dahdi-channels.conf
; Span 1: WCT1/0 "Digium Wildcard TE110P T1/E1 Card 0" (MASTER) HDB3/CCS/CRC4
group=0,11
context=from-pstn
switchtype = euroisdn
signalling = pri_cpe
channel => 1-15,17-31
context = default
group = 63
# cat /etc/asterisk/dahdi-channels.conf
; Span 1: WCT1/0 "Digium Wildcard TE110P T1/E1 Card 0" (MASTER) HDB3/CCS/CRC4
group=0,11
context=from-pstn
switchtype = euroisdn
signalling = pri_cpe
channel => 1-15,17-31
context = default
group = 63
Restart dahdi after applying the settings
*******
pri_net & pri_cpe control who acts like the "ISDN Network" and who acts like the "ISDN Customer Equipment". When you connect to a telco provided PRI, you'll want to set to "pri_cpe" *and* set the span in dahdi.conf to take clock from the line because you are customer equipment. If you are plugging your asterisk box into a PBX or something that is not a telco provided, you'll want to be set to "pri_net" because you are pretending to be the telephone network and you want to set the span in dahdi.conf to be timing level "0" to provide clock out onto the line.
*******
Check on dahdi status
From console
# asterisk -vvvr
dahdi show channels
dahdi show status
