apres avoir compilé libpri 1.4.10.2 j'ai lancé la commande " dahdi_cfg"
[root@localhost ~]# dahdi_cfg
[root@localhost ~]#

par contre la commande " dahdi_cfg -vvv" a donné ceci:
[root@localhost ~]# dahdi_cfg -vvv
DAHDI Tools Version - 2.4.1

DAHDI Version: 2.4.1.2
Echo Canceller(s): MG2
Configuration
======================

SPAN 1: CCS/ AMI Build-out: 0 db (CSU)/0-133 feet (DSX-1)
SPAN 2: CCS/ AMI Build-out: 0 db (CSU)/0-133 feet (DSX-1)
SPAN 3: CCS/ AMI Build-out: 0 db (CSU)/0-133 feet (DSX-1)
SPAN 4: CCS/ AMI Build-out: 0 db (CSU)/0-133 feet (DSX-1)

Channel map:

Channel 01: Clear channel (Default) (Echo Canceler: mg2) (Slaves: 01)
Channel 02: Clear channel (Default) (Echo Canceler: mg2) (Slaves: 02)
Channel 03: Hardware assisted D-channel (Default) (Echo Canceler: none) (Slaves: 03)
Channel 04: Clear channel (Default) (Echo Canceler: mg2) (Slaves: 04)
Channel 05: Clear channel (Default) (Echo Canceler: mg2) (Slaves: 05)
Channel 06: Hardware assisted D-channel (Default) (Echo Canceler: none) (Slaves: 06)
Channel 07: Clear channel (Default) (Echo Canceler: mg2) (Slaves: 07)
Channel 08: Clear channel (Default) (Echo Canceler: mg2) (Slaves: 08)
Channel 09: Hardware assisted D-channel (Default) (Echo Canceler: none) (Slaves: 09)
Channel 10: Clear channel (Default) (Echo Canceler: mg2) (Slaves: 10)
Channel 11: Clear channel (Default) (Echo Canceler: mg2) (Slaves: 11)
Channel 12: Hardware assisted D-channel (Default) (Echo Canceler: none) (Slaves: 12)

12 channels to configure.

Setting echocan for channel 1 to mg2
Setting echocan for channel 2 to mg2
Setting echocan for channel 3 to none
Setting echocan for channel 4 to mg2
Setting echocan for channel 5 to mg2
Setting echocan for channel 6 to none
Setting echocan for channel 7 to mg2
Setting echocan for channel 8 to mg2
Setting echocan for channel 9 to none
Setting echocan for channel 10 to mg2
Setting echocan for channel 11 to mg2
Setting echocan for channel 12 to none
[root@localhost ~]#

Cdlt;