asterisk users - May 2005 - High CPU in Asterisk, chan_unicall and dtmf

Hi, 

I have installed chan_unicall for MFCR2 on Asterisk 1.0.7, 1.0.5 and 1.0.4.

- 1.0.7 does not send dtmf properly through unicall channels from sip snom
phones on any mode (rfc2833, info, inband)
- 1.0.5 and 1.0.4 are able to send correctly the dtmf tones when configured
to INFO in sip.conf.

Could this be a problem inside 1.0.7 when paired with libunicall ?

Either version I am using, the cpu goes up to 99% sometimes (with 3 or more
calls) so the audio is choppy and you can't talk.  

I am trying to figure out what could be causing the problem high cpu usage.
I have tried to compile Asterisk with the profiling and debugging option
without success, any suggestion is welcome to identified the hotspot in the
code causing this ?

So far I have tested the following to see if the 99% CPU go away:

I am using CentOS 3.4 with Kernel  2.4.21-32.0.1.EL which is bundled from
Asterisk@Home iso version 1.0.

1. Changed motherboard to see if this is a related problem
	- I have tested 2 uniprocessor motherboards (One Gbyte, the other
Asrock)
	- I have tested and old Pentium III dual motherboard with APIC
controller with same high cpu.
	- I have tested with echo cancel, without echo cancel.
	- I have tried all possible echo cancellers by recompiling zaptel
with zconfig.h options
	- I have renamed mpg123 process to see if this is the problem
	- I have created a simple extensions.conf with the same problem (I
thought that dialparties.agi that came with Asterisk@home could be causing
this problem)
	- I have tried to boot the kernel with noapic and acpi=no kernel
directives.

Please let me know if you have any suggestion with this or something we
could try.

Regards.
	AM.