lakshmee

In addition to the config of both routers it may be helpful if you would post the output of show isdn status on both routers.

HTH

Rick

Bajaj-TVL#sh isdn status

Global ISDN Switchtype = basic-net3

ISDN BRI0/0/0 interface

dsl 0, interface ISDN Switchtype = basic-net3

Layer 1 Status:

ACTIVE

Layer 2 Status:

TEI = 64, Ces = 1, SAPI = 0, State = MULTIPLE_FRAME_ESTABLISHED

Layer 3 Status:

2 Active Layer 3 Call(s)

CCB:callid=802D, sapi=0, ces=1, B-chan=1, calltype=DATA, hdlctype=HDLC-TRUNK

CCB:callid=802E, sapi=0, ces=1, B-chan=2, calltype=DATA, hdlctype=HDLC-TRUNK

Active dsl 0 CCBs = 2

The Free Channel Mask: 0x80000000

at this time the isdn layer is active in 1841 but it not active always sometimes it shows "layer1 is deactivated".But in 2600 series router it is active always