[asterisk-users] E1 Channel Numbering - Your Comments.

[Andrew Latham]

All

This is a small issue that I stumbled onto that has to do with the
channel numbering on an E1 connection into an Asterisk Zaptel/DAHDI
system.

As most of us already know an E1 has 32 channels of which 30(1-15
17-31) are B-channels and 1 (16) is a D-Channel.  The 32nd channel is
not presented in Asterisk Zaptel/DAHDI.  There are other
configurations but this is the most common.

*** Everything currently works and the community is humming along with
the current implementation. ***

Is it or would it be worth the time to note the 32nd channel of the
E1?  I noticed this issue on a 4 port card with 4 E1s.  I quickly
expected the last B-channel at 127 where it was actually at 124 (my
first time with E1s).  As telcom lingo goes I have seen this 32nd
channel referred to as "time slot 0" and as "framing channel" and
expect there to be other names as well.

As an example, the current method:

bchan=1-15
dchan=16
bchan=17-31
...
bchan=32-46
dchan=47
bchan=48-62
...
bchan=63-77
dchan=78
bchan=79-93
...
bchan=94-108
dchan=109
bchan=110-124

and an example of my first thoughts:

bchan=1-15
dchan=16
bchan=17-31
uchan=32
...
bchan=33-47
dchan=48
bchan=49-63
uchan=64
...
bchan=65-79
dchan=80
bchan=81-95
uchan=96
...
bchan=97-111
dchan=112
bchan=113-127
uchan=128

I quickly grabbed the "uchan" to mean "Unused" or "Unallocated".  I am
going to assume that there are some better ideas and names for this.
One thought was "Framing" or "fchan" which does not exactly describe
the channel.  I did notice that depending on your locale the channel
had several names.


What are your ideas?




~
Andrew "lathama" Latham
lathama at gmail.com

* Learn more about OSS http://en.wikipedia.org/wiki/Open-source_software
* Learn more about Linux http://en.wikipedia.org/wiki/Linux
* Learn more about Tux http://en.wikipedia.org/wiki/Tux