3CX to Avaya integration - SIP Trunk

Many of our clients host 3CX on Claudion cloud servers, have existing Avaya boxes on-premises. Generally these Avaya IP Office boxes connected to PRI ( T1/E1 ) Line to ISPs/DID providers.

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Several of our clients host 3CX on Claudion cloud servers, have existing Avaya boxes on-premises. Generally these Avaya IP Office boxes connected to PRI ( T1/E1 ) Line to ISPs/DID providers.


This document explains how to connect between Avaya and 3CX using SIP tunks. This document assumes there is connectivity between 3CX and Avaya, either through VPN or direct cable. If there is a firewall between 3CX and Avaya, relevant ports must be open ( Typically use 5060 or 5061 and RTP ports. )


Below graphics are self explanatory.


3CX Configurations

1)Create One SIP trunk in 3CX to Avaya .

SIP Trunk in New Trunk Generic SIP Trunk , 3cx by giving peer IP, No authentication





DID Inbound Route : for Call Center Queue

Set the DID 2000 to the destination Queue 800



** Here, While receiving calls, The agents can see caller as XXX16209:800(XXX16209) like this. So To

make it simple as XXX16209,Do the following.

**In Parameters, Search for CID and you will get two options called APPENDCIDQUEUE and

PREPENDNAMETOCID. Set both values to zero.



Outbound Route 1: for Avaya extensions



Outbound Route 2 : for External Calls through Avaya



**While calling outside, 3CX will append 123 to the called_number. Ex:If an agent calls 44112233, Called

number will be translated as 12344112233. So that avaya can identify call is coming from 3CX and need

to be routed external through PRI.


Avaya Configurations


Create a SIP trunk without authentication





**ITSP domain name is the ip address of Avaya PBX.

**Check OOS must be off, Otherwise you may receive SIP error “service unavailable” on calling.





The above is for Avaya verison below 11 . For 11+ see the image below. I dont have a high resolutions picture. sorry about that






**Use Audio Codec G711alaw and G711ulaw only

Inbound Route : Receive calls from main number 44197997 and pass to 3cx

Expand incoming call route and select DID 7997 and give destination 8200. Here “0” is the PRI Line

Incoming group ID(0)

Then Avaya Check for an ARS matching 82000.




Avaya Matches an ARS with 8200 here;




**Finally, Incoming call received on DID 44197997 will be routed to 2000 (3CX Trunk Number)


Outbound Route for Making External Calls from 3CX agents

In 3CX, We have translated the outbound calls by prepending 123 to the called number and routed to

Avaya. Now Avaya Will search for an ARS with which starts with 123 as prefix.



Here Line group ID:0 is the PRI outgoing group ID. So, the calls will be routed to PRI Trunk by removing

prefix 123. Expression <NS”44197997”> is used to bind the source as 44197997 for External Calls.


Hope this will help. We are ready to support in case you face any issues - send mail to support@claudion.com


Farook Kalpana

Senior consultant

1 comment
Ahmed January 20, 2022

Hello Thanks for ur effort Something does not understand Where have i add 3cx ip address in avaya ? and if you could share diagram with ip adress would be good

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