1) Channel Groups.
DAHDI/g1/5551212 dials 5551212 on the first available channel in group
one, searching from lowest to highest
DAHDI/G1/5551212 dials 5551212 on the first available channel in group
one, searching from highest to lowest
DAHDI/r1/5551212 dials 5551212 on the first available channel in group
one, going in round-robin fashion (and remembering where it last left
off), searching from lowest to highest
DAHDI/R1/5551212 dials 5551212 on the first available channel in group
one, searching in round-robin fashion from highest to lowest.
2) Distinctive ring
DAHDI/4r1 dials channel 4 (presumably an FXS channel), and uses
distinctive ring style one. If I recall, there are four different
distinctive ring styles... so you could replace r1 with r2, r3, or r4.
3) Answer confirmation
DAHDI/1c/5551212 tells Asterisk to dial 5551212 on DAHDI channel 1, and
not consider the call answered until the called party presses #. This
is useful because of the way analog signaling works. Without this
setting, Asterisk considers any outbound analog call on an FXO port
answered just as soon as it has been dialed.
4) Digital calls
DAHDI/1d/5551212 tells Asterisk to dial 5551212 on DAHDI channel 1, and
that it's a digital call. If I remember correctly, this is used for
ISDN calls to set the bearer capability.
I've taken a quick look in channels/chan_dahdi.c in TRUNK, and it seems
to match up with my understanding, as I didn't see any other options
stand out. While poking around in there, I found the following comment:
/*
* data is ---v
* Dial(DAHDI/pseudo[/extension])
* Dial(DAHDI/<channel#>[c|r<cadance#>|d][/extension])
* Dial(DAHDI/(g|G|r|R)<group#(0-63)>[c|r<cadance#>|d][/extension])
*
* g - channel group allocation search forward
* G - channel group allocation search backward
* r - channel group allocation round robin search forward
* R - channel group allocation round robin search backward
*
* c - Wait for DTMF digit to confirm answer
* r<cadance#> - Set distintive ring cadance number
* d - Force bearer capability for ISDN/SS7 call to digital.
*/
