AEX800

The Digium AEX800 card supports up to 8 POTS lines. The AEX800 card can support a single or quad FXS or FXO module. This card is the same as the TDM800P with the exception of the BUS type.
File:aex800.png

/etc/dahdi/modules

# Digium TDM2400P/AEX2400: up to 24 analog ports
# Digium TDM800P/AEX800: up to 8 analog ports
# Digium TDM410P/AEX410: up to 4 analog ports
wctdm24xxp

For a card that has one Quad FXO module installed. /etc/dahdi/system.conf

loadzone = au
defaultzone=au
fxsks=1-4
echocanceller=mg2,1-4

If you have a hardware echo cancellation module installed

echocanceller=hpec,1-4

/etc/asterisk/chan_dahdi.conf

language=au
context=Telstra
usecallerid=yes
callwaiting=no
threewaycalling=no
transfer=yes
canpark=yes
echocancel=yes
echocancelwhenbridged=yes

context=Telstra-tech42
group=1
signalling=fxs_ks
channel => 1-2