asterisk users - Nov 2004 - Garbled sound - CPU or traffic problem?

Hi!

I'm using asterisk on my local server. An analog phone is connected to a 
PhoneJack lite. The computer (PII-333) is connected to the internet via DSL.

Sometimes the sound is really clear, as if it was a normal telephone 
call. But there are times too, when I hear the other person really 
garbled. That means the sound is disturbed with little breaks. The 
problem seems to occur on both sides.

I used ULAW as speech codec.

Is my cpu too slow? Could it be a problem with my connection? I do not 
use a donkey-client or something else.

What can I do to analyse where this problem comes from?

Could it be a problem with my SIP-Provider? (Sipgate)

Bye!

Michael