asterisk users - Jan 2005 - Delay before dialing extension on Zap channel

Hi,

After using Asterisk with a SIP hardphone for a couple of weeks I've just 
installed a TDM400P card.

My hardphone - a 7940 - allows me to use a dialplan to decide when a 
particular extension is complete and automatically trigger dialing.  This 
works well with my internal extensions, which are all of the form
"Z00".

When trying to dial these extensions from a handset connected to a Zap 
channel there appears to be a delay of about 4 seconds between the time I
dial "Z00" and the time asterisk decides I've finished dialing and
connects me.

Is there any way to reduce this delay?  I'd ideally like asterisk to dial 
the extension as soon as it matches a valid extension.


-Ronan