[asterisk-users] "requested special control 20" ??

[sean darcy]

I'm using Teliax, and every incoming call has:

Executing [yyyxxxxxxx at teliax-in:2] Answer("IAX2/usrname-14376", "") in 
new stack
     -- Executing [yyyxxxxxx at teliax-in:3] Dial("IAX2/usrname-14376", 
"DAHDI/1,60") in new stack
     -- Called 1
     -- DAHDI/1-1 is ringing
     -- IAX2/usrname-14376 requested special control 20, passing it to 
DAHDI/1-1
     -- IAX2/usrname-14376 requested special control 20, passing it to 
DAHDI/1-1
     -- DAHDI/1-1 is ringing


It all seems to work OK, but what's "requesting special control 20" all 
about?

sean