Incoming DAHDI Channel Explained

Home » Asterisk Users » Incoming DAHDI Channel Explained
Asterisk Users 4 Comments


I use a Sangoma A104d-Card (with 4 x germany E1). I process some calls via an AGI-Script. When parsing the AGI-Variables I can see one that look like that:

[agi_channel] => DAHDI/i3/211123456-89c

What hat do the values mean in detail, please?

DAHDI : this is clear i3 : does it mean, that the call comes in via E1-Port 3?
211123456 : Incoming-Call Caller-ID
-89c : ?

WANPIPE Release: 7.0.1
DAHDI Version: 2.6.2 Echo Canceller: HWEC
libpri version: 1.4.12

Best regards

4 thoughts on - Incoming DAHDI Channel Explained

  • Sangoma’s tech support is probably the better source of information.

    DAHDI: obviously DAHDI channel i: incoming call
    3: span 3 (not the port)
    211123456: CLID, probably subject to filtering (see national/international prefix settings)
    89c: internal counter (i.e. 2204 calls so far)


  • The ‘i’ is for ISDN not incoming call since it will be this way for outgoing calls as well.

    The other fields are pretty much as described by jg.


  • Yes, my assumption was wrong and to make things worse, my CDR data clearly show that “i” cannot denote incoming calls.

    Maybe it’s time that I learn the rules as well:

    Analog channels do not seem to have a special identifier. The 1st call for analog channel 13 would be like DAHDI/13-1.

    Outside calls via an ISDN connection with like DIAL(DAHDI/r2/08932168,..) would dial the number using DAHDI group 2 in a round robin fashion, but internally the channel would be like DAHDI/iX/08932168-abcd. The span X is not related to the dial group and depends on the configuration.

    For a BRI device a single span has 2 channels, a PRI device up to 30. As far as channel variables go the actual channel does not seem to get reported, but this is not really necessary.


  • B.H.


    For a BRI device a single span has 2 channels, a PRI device up to 30. As

    AFAIK, at least for AMI listeners, the real channel/span is reported by DAHDIChannelEvent attributes:

    ‘dahdichannel’ reports the actual DAHDI channel number
    ‘dahdispan’ is a span number