asterisk users - Jun 2004 - curious (and incorrect) caller*id behavior

Hi-

I have an FXO module in my TDM400P configured to receive caller*id (see 
zapata.conf below). I get a curious behavior: When I call this line 
with my cell phone, I see caller ID received just fine, with no 
warnings or errors.. When I call from another landline, I get different 
results:

calling from external line, caller ID off:
WARNING[1233021872]: chan_zap.c:4980 ss_thread: CallerID returned with 
error on channel 'Zap/3-1'

calling from another line at the same premises, caller*id off:
ERROR[1233021872]: callerid.c:193 callerid_feed: fsk_serie made mylen < 
0 (-6)
WARNING[1233021872]: chan_zap.c:4938 ss_thread: CallerID feed failed: 
Success
WARNING[1233021872]: chan_zap.c:4980 ss_thread: CallerID returned with 
error on channel 'Zap/3-1'

calling from same line as previous, caller*ID explicitly ON (*82, ... 
-- confirmed with another phone)
ERROR[1233021872]: callerid.c:193 callerid_feed: fsk_serie made mylen < 
0 (-12)
WARNING[1233021872]: chan_zap.c:4938 ss_thread: CallerID feed failed: 
Success
WARNING[1233021872]: chan_zap.c:4980 ss_thread: CallerID returned with 
error on channel 'Zap/3-1'


I'm running CVS top of tree from today.

Possibly related information (or not): the line coming into the FXO 
module also is used for DSL. A decent filter is installed.

zapata.conf section for this FXO module:

signalling=fxs_ks
echocancel=yes
busydetect=yes
callprogress=no
faxdetect=incoming
usecallerid=yes
callerid=asreceived
group=1
channel => 3

any help?

regards,
-- David