I did an interesting T1 config on a four port Digium card the other day. I’ll post what my config files look like and perhaps you can interpolate what you need to do for your system. Bare in mind, this is the most complicated T1 configuration I have done to date and I worked with Digium tech support to get it to work. I think an important point is that you need to configure system.conf correctly first, then run dahdi_cfg -vvv. I am not so sure the dahdi gui bit is up to complicated configurations.
/etc/dahdi/system.conf
Global data
loadzone = us
defaultzone = us
span=1,1,0,esf,b8zs
e&m=1-12
fxsks=13-24
echocanceller=mg2,1-24
span=2,0,0,esf,b8zs
fxoks=25-48
echocanceller=mg2,25-48
span=3,0,0,esf,b8zs
fxoks=49-72
echocanceller=mg2,49-72
span=4,0,0,esf,b8zs
fxoks=73-96
echocanceller=mg2,73-96
XXX_________
/etc/asterisk/chan_dahdi.conf
[trunkgroups]
[channels]
language=en
#include dahdi-channels.conf
XXXX______
/etc/asterisk/dahdi-channels.conf
group=0
signalling=em_w
context=from-pstn
usecallerid=yes
echocancel=yes
channel=1-6
group=1
signalling=em_w
context=from-pstn
usecallerid=yes
echocancel=yes
channel=7-8
group=2
signalling=em_w
context=from-internal
usecallerid=yes
echocancel=yes
channel=9-12
group=3
signalling=fxs_ks
context=from-pstn
usecallerid=yes
echocancel=yes
channel=13-24
group=4
signalling=fxo_ks
context=from-internal
usecallerid=yes
echocancel=yes
channel=25-96
; include dahdi extensions defined in FreePBX
#include chan_dahdi_additional.conf
XXXXXXXXX_
[root@localhost ~]# asterisk -rx "dahdi show channels"
Chan Extension Context Language MOH Interpret Blocked State
pseudo default default In Service
1 from-pstn en default In Service
2 from-pstn en default In Service
3 from-pstn en default In Service
4 from-pstn en default In Service
5 from-pstn en default In Service
6 from-pstn en default In Service
7 from-pstn en default In Service
8 from-pstn en default In Service
9 from-internal en default In Service
10 from-internal en default In Service
11 from-internal en default In Service
12 from-internal en default In Service
13 from-pstn en default In Service
14 from-pstn en default In Service
15 from-pstn en default In Service
16 from-pstn en default In Service
17 from-pstn en default In Service
18 from-pstn en default In Service
19 from-pstn en default In Service
20 from-pstn en default In Service
21 from-pstn en default In Service
22 from-pstn en default In Service
23 from-pstn en default In Service
24 from-pstn en default In Service
25 from-internal en default In Service
26 from-internal en default In Service
27 from-internal en default In Service
28 from-internal en default In Service
29 from-internal en default In Service
30 from-internal en default In Service
31 from-internal en default In Service
32 from-internal en default In Service
33 from-internal en default In Service
34 from-internal en default In Service
35 from-internal en default In Service
36 from-internal en default In Service
37 from-internal en default In Service
38 from-internal en default In Service
39 from-internal en default In Service
40 from-internal en default In Service
41 from-internal en default In Service
42 from-internal en default In Service
43 from-internal en default In Service
44 from-internal en default In Service
45 from-internal en default In Service
46 from-internal en default In Service
47 from-internal en default In Service
48 from-internal en default In Service
49 from-internal en default In Service
50 from-internal en default In Service
51 from-internal en default In Service
52 from-internal en default In Service
53 from-internal en default In Service
54 from-internal en default In Service
55 from-internal en default In Service
56 from-internal en default In Service
57 from-internal en default In Service
58 from-internal en default In Service
59 from-internal en default In Service
60 from-internal en default In Service
61 from-internal en default In Service
62 from-internal en default In Service
63 from-internal en default In Service
64 from-internal en default In Service
65 from-internal en default In Service
66 from-internal en default In Service
67 from-internal en default In Service
68 from-internal en default In Service
69 from-internal en default In Service
70 from-internal en default In Service
71 from-internal en default In Service
72 from-internal en default In Service
73 from-internal en default In Service
74 from-internal en default In Service
75 from-internal en default In Service
76 from-internal en default In Service
77 from-internal en default In Service
78 from-internal en default In Service
79 from-internal en default In Service
80 from-internal en default In Service
81 from-internal en default In Service
82 from-internal en default In Service
83 from-internal en default In Service
84 from-internal en default In Service
85 from-internal en default In Service
86 from-internal en default In Service
87 from-internal en default In Service
88 from-internal en default In Service
89 from-internal en default In Service
90 from-internal en default In Service
91 from-internal en default In Service
92 from-internal en default In Service
93 from-internal en default In Service
94 from-internal en default In Service
95 from-internal en default In Service
96 from-internal en default In Service
XXXX___