For Greece, OTE, the signalling is ptmp.
Hence, the configs below apply for ISDN BRI B400P and TDM400P PSTN:

system.conf:
Span 1: B4/0/1 “B4XXP (PCI) Card 0 Span 1” (MASTER)
span=1,1,0,ccs,ami
# termtype: te
bchan=1-2
hardhdlc=3
echocanceller=oslec,1-2

# Span 2: B4/0/2 “B4XXP (PCI) Card 0 Span 2”
span=2,2,0,ccs,ami
# termtype: te
bchan=4-5
hardhdlc=6
echocanceller=oslec,4-5

# Span 3: WCTDM/4 “Wildcard TDM400P REV E/F Board 5”
fxsks=7
echocanceller=oslec,7
# channel 8, WCTDM/4/1, no module.
# channel 9, WCTDM/4/2, no module.
# channel 10, WCTDM/4/3, no module.

# Global data

loadzone = gr
defaultzone = gr

genconf_parameters:
echo_can oslec
bri_sig_style bri_ptmp
context_lines from-zaptel
lc_country gr

chan_dahdi.conf:
[trunkgroups]

[channels]
context=from-pstn
signalling=fxs_ks
rxwink=300 ; Atlas seems to use long (250ms) winks
usecallerid=yes
hidecallerid=no
callwaiting=yes
usecallingpres=yes
callwaitingcallerid=yes
threewaycalling=yes
transfer=yes
canpark=yes
cancallforward=yes
callreturn=yes
echocancel=yes
echocancelwhenbridged=no
faxdetect=incoming
echotraining=800
rxgain=0.0
txgain=0.0
callgroup=1
pickupgroup=1
relaxdtmf=yes

;Uncomment these lines if you have problems with the disconection of your analog lines
;busydetect=yes
;busycount=3

immediate=no

#include dahdi-channels.conf
#include chan_dahdi_additional.conf

You should get most of them by auto detecting hardware. However, if it does not work, you got them!