asterisk users - Jan 2006 - spandsp, rxfax, TDM400/zaptel, missed frames, any help?

Sorry in advance if this is a FAQ...

I've got a working Asterisk setup based on A@H 2.2. I have a TDM400
card with 2 FXS and 2 FXO ports; PSTN connections come in via the TDM
card.

I haven't been able to get inbound fax with spandsp and rxfax to work.
Occasionally an all-text fax will come in, though it's usually badly
corrupted, but in most cases, it would appear that the call is
terminated without successful transmission of the fax. I get logs that
look what's included below.
>From reading the list, it looks like this is caused by the TDM card
missing frames. Does that sound correct? If so, is there any relief in
sight?

Thanks for the help.

Ben

Jan  8 21:47:53 VERBOSE[17842] logger.c:     -- Goto (ext-fax,in_fax,2)
Jan  8 21:47:53 VERBOSE[17842] logger.c:     -- Executing
Macro("Zap/3-1", "faxreceive") in new stack
Jan  8 21:47:53 VERBOSE[17842] logger.c:     -- Executing
SetVar("Zap/3-1",
FAXFILE=/var/spool/asterisk/fax/1136774870.55.tif")
in new stack
Jan  8 21:47:53 VERBOSE[17842] logger.c:     -- Executing
SetVar("Zap/3-1", "EMAILADDR=[redacted]") in new stack
Jan  8 21:47:53 VERBOSE[17842] logger.c:     -- Executing
RxFAX("Zap/3-1",
"/var/spool/asterisk/fax/1136774870.55.tif") in new
stack
Jan  8 21:48:21 DEBUG[17842] chan_zap.c: Exception on 14, channel 3
Jan  8 21:48:21 DEBUG[17842] chan_zap.c: Got event On hook(1) on
channel 3 (index 0)
Jan  8 21:48:21 DEBUG[17842] chan_zap.c: disabled echo cancellation on channel 3
Jan  8 21:48:21 DEBUG[17842] app_rxfax.c: Got hangup
Jan  8 21:48:21 DEBUG[17842] app_macro.c: Extension s, priority 3
returned normally even though call was hung up
Jan  8 21:48:21 DEBUG[17842] pbx.c: Extension in_fax, priority 2
returned normally even though call was hung up
Jan  8 21:48:21 VERBOSE[17842] logger.c:     -- Executing
Hangup("Zap/3-1", "") in new stack
Jan  8 21:48:21 VERBOSE[17842] logger.c:   == Spawn extension
(ext-fax, h, 1) exited non-zero on 'Zap/3-1'
Jan  8 21:48:21 DEBUG[17842] cdr_addon_mysql.c: cdr_mysql: inserting a
CDR record.
Jan  8 21:48:21 DEBUG[17842] cdr_addon_mysql.c: cdr_mysql: SQL command
as follows: INSERT INTO cdr
(calldate,clid,src,dst,dcontext,channel,dstchannel,lastapp,lastdata,duration,billsec,disposition,amaflags,accountcode,uniqueid)
VALUES
('2006-01-08
21:47:51','','','in_fax','ext-fax',
'Zap/3-1','','Hangup','',30,30,'ANSWERED',3,'','1136774870.55')
Jan  8 21:48:21 DEBUG[17842] chan_zap.c: Hangup: channel: 3 index = 0,
normal = 14, callwait = -1, thirdcall = -1
Jan  8 21:48:21 DEBUG[17842] chan_zap.c: disabled echo cancellation on channel 3
Jan  8 21:48:21 DEBUG[17842] chan_zap.c: Set option TDD MODE, value:
OFF(0) on Zap/3-1
Jan  8 21:48:21 DEBUG[17842] chan_zap.c: Updated conferencing on 3,
with 0 conference users
Jan  8 21:48:21 VERBOSE[17842] logger.c:     -- Hungup 'Zap/3-1'

> Sorry in advance if this is a FAQ...
> 
> I've got a working Asterisk setup based on A@H 2.2. I have a TDM400
> card with 2 FXS and 2 FXO ports; PSTN connections come in via the TDM
> card.
> 
> I haven't been able to get inbound fax with spandsp and rxfax to work.
> Occasionally an all-text fax will come in, though it's usually badly
> corrupted, but in most cases, it would appear that the call is
> terminated without successful transmission of the fax. I get logs that
> look what's included below.
> 
> >From reading the list, it looks like this is caused by the TDM card
> missing frames. Does that sound correct? If so, is there any relief in
> sight?
Its been a problem since the card came out a couple of years ago. So, no
it does not appear there is any relief in sight.