[Asterisk-Users] GR-303 configuration options?

[Chris A. Icide]

Can anyone describe the asterisk implementation of this any better than the 
sample config files do?

from zapata.conf

; Trunk groups are used for NFAS or GR-303 connections.
;
; Group: Defines a trunk group.
;        group => <trunkgroup>,<dchannel>[,<backup1>...]
;
;        trunkgroup  is the numerical trunk group to create
;        dchannel    is the zap channel which will have the
;                    d-channel for the trunk.
;        backup1     is an optional list of backup d-channels.
;
;trunkgroup => 1,24,48
;
; Spanmap: Associates a span with a trunk group
;        spanmap => <zapspan>,<trunkgroup>[,<logicalspan>]
;
;        zapspan     is the zap span number to associate
;        trunkgroup  is the trunkgroup (specified above) for the mapping
;        logicalspan is the logical span number within the trunk group to use.
;                    if unspecified, no logical span number is used.
;
;spanmap => 1,1,1
;spanmap => 2,1,2
;spanmap => 3,1,3
;spanmap => 4,1,4


the trunkgroup seems self explanatory.  If I'm reading this correctly, 
trunkgroup=x,y,z  creates a logical trunk group identified by x, with y as 
the signalling channel (which can contain up to 4 actual signalling 
channels?), and z being one or more signalling backup channels (also 
carrying as many as 4 signalling channels in one DS0 channel)

spanmap => <zapspan>,<trunkgroup>,<logicalspan>

so this seems to be an entry that will tie the logical trunkgroup to the 
physical T1 span, but what exactly is the purpose of the 'logicalspan' entry?


next lower in the config we have the crv entries, which replace the well 
known channel entries used in other signalling methods.

; For GR-303, CRV's are created like channels except they must start
; with the trunk group followed by a colon, e.g.:
;
; crv => 1:1
; crv => 2:1-2,5-8


so again, the first entry in a crv references the logical trunk group, 
correct? and the second and following entries define GR-303 CRV channels?

so crv => 1:1 would reference GR-303 channel 1 on logical trunk 1?

since GR-303 allows oversubscription of channels, does that mean that 
asterisk handles this correctly?  If we had a single T1 interface going to 
a channel bank using GR-303, would asterisk understand:

crv => 1:45

in this case if I dialed Zap span 1 channel 45, would asterisk understand 
this correctly in it's GR-303 implementation?


Also on a final note, does anyone know what the user of an analog phone 
connected to an Adit 600, which uses GR-303 trunking hears when they go to 
use thier phone and all the trunk lines are active?

-Chris