asterisk users - May 2006 - Using console channel with specific codec only

Hi,

I configured a console channel for my sound card and assigned an 
extension to it. That way, I am able to talk to any SIP account when 
they call this extension. For testing purposes, I now would like to be 
able to allow only one specific codec and reject all calls to the 
console with other codecs. Problem is, the mechanism with allow/disallow 
only works for SIP accounts.
Any suggestions on how to accomplish this?

Thanks,
Patrick