[Asterisk-Users] s / i extension difficulty

[Tyler Retzlaff]

I'm having some difficulty with s extensions.  For some reason they  
don't seem to be matching anything.

The documentation says that The "s" extension is used when there is  
no known called number in the context used.
I must be misinterpreting what this means.  I take this to mean that  
if the extension dialed does not match any other
extension defined in the context then the s extension is used.

So I have.

[incoming-sip]
exten => s,1,Answer
exten => s,n,Playback(enter-ext-of-person)
exten => s,n,Hangup

exten => 522,1,Answer
exten => 522,n,Playback(enter-ext-of-person)
exten => 522,n,Hangup

If I dial 522 I get the incoming-sip context I hear the playback as  
expected.
If I dial 523 (an extension that isn't matched) I just get a 404 not  
found, but I expected to get the playback.

How is the s extension matched? (asterisk 1.2.9.1)
Have I misinterpreted how the s extension is matched?

Thanks

Tyler