# The Asterisk(R) Open Source PBX
# By Mark Spencer <[email protected]> and the Asterisk.org developer community.
# Copyright (C) 2001-2025 Sangoma Technologies Corporation and other copyright holders.

; Description of a solution used as a customized Dialplan to provide call routing on the same Telco line to Asterisk SIP users/EXTs for incoming and outgoing calls using call access level/restrictions
; Example -- Fixed Telco Phone Line - 0290 389 038
; As we can see from the config files (chan_dahdi.conf, extensions.conf and sip.conf) in order for this scenario to work properly -- the calls coming to  0290 389 038 and originated through this external Telco phone line 0290 389 038, it needs these configs:
; This solution is applied when you have in use different single telephone lines from your provider and not E1 trunk or SIP trunk which are different scenarios and more easy to implement incoming and outgoing calls because they use same number for 30 or more channels.

chan_dahdi.conf

; Span 1: WCTDM/0 "Wildcard A4B" (MASTER) 
; line="2 WCTDM/0/1 FXSKS  (EC: VPMOCT032 - INACTIVE)"
signalling=fxs_ks
callerid=asreceived
group=0
context=from-0290389038          ; here context needs to be defined to match with dialplan context for incoming call
channel => 2


extensions.conf

[from-0290389038]                ;the context here defines where/on which SIP user/EXT the incoming calls through external line 0290389038 will go to internal SIP lines -- on this case EXT 3202
exten => s,1,Dial(SIP/3202,45)
same => n,Hangup()


sip.conf

[3202]
deny=0.0.0.0/0.0.0.0
secret=xxxx
dtmfmode=rfc2833
canreinvite=no
context=mobil_via_0290389038       ; for outgoing calls we see here that EXT 32302  uses the exact external line 0290 389 038  to send calls out - it has access level mobil_via_0290389038 defined on dialplan as we can see below 
host=dynamic
defaultuser=
trustrpid=yes
sendrpid=pai
type=friend
session-timers=accept
nat=no
port=5060
qualify=yes
qualifyfreq=60
transport=udp
avpf=no
force_avp=no
icesupport=no
rtcp_mux=no
encryption=no
namedcallgroup=
namedpickupgroup=
dial=SIP/3202
permit=0.0.0.0/0.0.0.0
callerid=xyzrks <3202>
callcounter=yes
faxdetect=no
cc_monitor_policy=generic



;to explain outgoing calls for EXT 3202 in more details and continue the logic as we can see we have defined these calls towards mobile numbers 044, 048, .... etc on extensions.conf like this:

extensions.conf

[mobil_via_0290389038]  ; ******* LINE 2 - MOBILE CALLS ACCESS **********
; Calls to MOBILE OPERATORS/Numbers through Dahdi channel 2/Telco Line 2 connected on port 2 of Dahdi/digium/sangoma FXO card -- MOBILE CALLS - CHANNEL 2

exten => _044XXXX.,1,Dial(DAHDI/2/${EXTEN},60)    ; we can see here that context mobil_via_0290389038 on which EXT 3202 has access level will use Dahdi channel 2 to send outgoing calls amd we now that dahdi port/channel 2 is line 0290 389 038 
same => n,Hangup()
exten => _045XXXX.,1,Dial(DAHDI/2/${EXTEN},60)
same => n,Hangup()
exten => _048XXXX.,1,Dial(DAHDI/2/${EXTEN},60)
same => n,Hangup()
include => fiks_via_0290389038


; So this dialplan makes possible using the same external phone line for incoming and outgoing calls as it is requested in lot of real life scenarios, to be defined exactely the same line/number and not use random lines for outgoing calls.
;**********The same process and function is for other lines too (1, 3 ... etc)